CiteULike: jyuh's animal

Local renal aldosterone production induces inflammation and matrix formation in kidneys of diabetic rats

Siragy — 2008-06-16T09:17:41-00:00

Experimental Physiology, Vol. 93, No. 7. (July 2008), pp. 817-824.

Curcumin protects against ischemia/reperfusion injury in rat kidneys

Bayrak — 2008-06-13T16:37:13-00:00

World Journal of Urology, Vol. 26, No. 3. (June 2008), pp. 285-291.

Antioxidant and protective effects of silymarin on ischemia and reperfusion injury in the kidney tissues of rats.

Faruk Turgut — 2008-06-29T05:38:26-00:00

International urology and nephrology (27 March 2008)

BACKGROUND: Renal ischemia/reperfusion (I/R) injury is a major cause of acute renal failure. Silymarin is extracted from Silybum marianum and Cynara cardunculus seeds and fruits. The aim of this study is to investigate whether silymarin administration prevents the damage induced by I/R in rat kidneys. MATERIALS AND METHODS: Thirty male Wistar rats were randomly divided into five experimental groups (n = 6, each) as follows; control group, sham-operated group, I/R group, silymarin group, and I/R + silymarin group. In the I/R and I/R + silymarin groups, both renal arteries were occluded using nontraumatic microvascular clamps for 45 min. Then, at the end of 24 h of reperfusion, the animals were killed. Kidney function tests, the serum and tissue antioxidant enzymes and oxidant products were determined. RESULTS: Animals that were subjected to I/R exhibited significant increase in serum urea, creatinine, and cystatin C levels compared with the rats treated with silymarin prior to the I/R process (P < 0.001). The serum enzymatic activities of superoxide dismutase and glutathione peroxidase significantly decreased in the I/R group; however, this reduction was significantly improved by the treatment with silymarin (P < 0.001 and P < 0.05, respectively). Renal I/R produced a significant increase in serum and tissue malondialdehyde, nitric oxide, and protein carbonyl as compared with controls. Treatment with silymarin resulted in significant reduction in these markers (P < 0.001). CONCLUSION: Based on our findings, silymarin protects the kidneys against I/R injury. This finding may provide a basis for the development of novel therapeutic strategies for protection against the damages caused by I/R.

The effects of high-fat diet on the renal structure and morphometric parametric of kidneys in rats

Altunkaynak — 2008-05-31T06:39:04-00:00

Journal of Anatomy, Vol. 212, No. 6. (June 2008), pp. 845-852.

HGF-MSP chimera protects kidneys from ischemia-reperfusion injury.

F Xue — 2008-06-29T03:01:17-00:00

Biochemical and biophysical research communications, Vol. 363, No. 2. (16 November 2007), pp. 451-456.

Renal ischemia-reperfusion (I/R) injury is inevitable in transplantation and is related to long-term graft function. MF-1, a bifunctional hepatocyte growth factor (HGF)-macrophage-stimulating protein (MSP) (HGF-MSP) chimera was recently reported to prevent apoptosis. We therefore hypothesized that treatment with MF-1 would protect kidneys from I/R injury by inhibiting tubular epithelial apoptosis. MF-1 directly guarded cultured proximal tubular epithelial cells from hypoxia-induced necrosis and apoptosis in vitro. In addition, the therapeutic effects of MF-1 were evaluated using a rat I/R injury model in vivo. Saline-treated kidneys had increased creatinine and BUN, and exhibited tubular epithelial apoptosis with activated caspase 3 expression. In contrast, MF-1 treatment up-regulated Akt phosphorylation, and inhibited caspase 3 activation and tubular apoptosis, thereby ameliorating renal dysfunction. Of particular interest is that macrophage infiltration was suppressed in the MF-1-treated kidney. In conclusion, we identified a novel therapeutic approach using MF-1 to protect kidneys from I/R injury.

Animal models of obesity-associated chronic kidney disease.

RH Mak — 2008-06-29T02:30:43-00:00

Advances in chronic kidney disease, Vol. 13, No. 4. (October 2006), pp. 374-385.

Dramatic advances in basic science have been made in the past 50 years on the basis of animal models of obesity and type II diabetes. Positional-cloning strategies in rodents with spontaneous obesity have enabled landmark scientific breakthroughs and defined the molecular scaffolding for the regulation of energy homeostasis. Recently, studies in the general population suggest that obesity is an independent risk factor for chronic kidney disease. To date, most of the animal studies that investigated chronic kidney disease associated with obesity and type II diabetes have largely been descriptive. We aim to provide an overview of animal models used to investigate the mechanisms of obesity-associated chronic kidney disease. Our overview is not meant to be an exhaustive list of all animal models in the literature on this subject, but rather to illustrate the experimental approaches. Because of space limitations, we have chosen to concentrate on rodent models. These animal models will provide excellent tools for in vivo testing of molecular mechanisms. Further hypothesis-driven research into the mechanism of chronic kidney disease and their progression by use of these models will provide important insights necessary to develop therapeutic strategies for this significant complication of the worldwide epidemic of obesity and type II diabetes.

Activated vitamin D attenuates left ventricular abnormalities induced by dietary sodium in Dahl salt-sensitive animals

Natalya Bodyak — 2008-06-17T03:33:56-00:00

Proceedings of the National Academy of Sciences, Vol. 104, No. 43. (23 October 2007), pp. 16810-16815.

Observations in hemodialysis patients suggest a survival advantage associated with activated vitamin D therapy. Left ventricular (LV) structural and functional abnormalities are strongly linked with hemodialysis mortality. Here, we investigated whether paricalcitol (PC, 19-nor-1,25(OH)2D2), an activated vitamin D compound, attenuates the development of LV abnormalities in the Dahl salt-sensitive (DSS) rat and whether humans demonstrate comparable findings. Compared with DSS rats fed a high-salt (HS) diet (6% NaCl for 6 weeks), HS+PC was associated with lower heart and lung weights, reduced LV mass, posterior wall thickness and end diastolic pressures, and increased fractional shortening. Blood pressures did not significantly differ between the HS groups. Plasma brain natriuretic peptide levels, and cardiac mRNA expression of brain natriuretic peptide, atrial natriuretic factor, and renin were significantly reduced in the HS+PC animals. Microarray analyses revealed 45 specific HS genes modified by PC. In a retrospective pilot study of hemodialysis patients, PC-treated subjects demonstrated improved diastolic function and a reduction in LV septal and posterior wall thickness by echocardiography compared with untreated patients. In summary, PC attenuates the development of LV alterations in DSS rats, and these effects should be examined in human clinical trials. 10.1073/pnas.0611202104

From the Cover: A drug-controllable tag for visualizing newly synthesized proteins in cells and whole animals

Michael Lin — 2008-06-10T10:20:00-00:00

Proceedings of the National Academy of Sciences, Vol. 105, No. 22. (3 June 2008), pp. 7744-7749.

Research on basic cellular processes involving local production or delivery of proteins, such as activity-dependent synaptic modification in neurons, would benefit greatly from a robust, nontoxic method to visualize selectively newly synthesized copies of proteins of interest within cells, tissues, or animals. We report a technique for covalent labeling of newly synthesized proteins of interest based on drug-dependent preservation of epitope tags. Epitope tags are removed from proteins of interest immediately after translation by the activity of a sequence-specific protease until the time a protease inhibitor is added, after which newly synthesized protein copies retain their tags. This method, which we call TimeSTAMP for time-specific tagging for the age measurement of proteins, allows sensitive and nonperturbative visualization and quantification of newly synthesized proteins of interest with exceptionally tight temporal control. We demonstrate applications of TimeSTAMP in retrospectively identifying growing synapses in cultured neurons and in visualizing the distribution of recently synthesized proteins in intact fly brains. 10.1073/pnas.0803060105

Justifying the number of animals for each experiment.

WC Eckelman — 2008-06-08T03:59:04-00:00

Nuclear medicine and biology, Vol. 34, No. 3. (April 2007), pp. 229-232.

Adaptation to hypoxia in the diabetic rat kidney.

C Rosenberger — 2008-05-31T07:19:25-00:00

Kidney international, Vol. 73, No. 1. (January 2008), pp. 34-42.

Hypoxia of the kidney in diabetes could predispose it to develop acute and chronic renal failure. To examine the relationship between renal hypoxia and renal failure, we measured hypoxia (as a pimonidazole adducts), hypoxia-inducible factors (HIFs), and a hypoxia target gene heme oxygenase-1. The studies were performed in rats with streptozotocin (STZ)-induced diabetes, Cohen diabetes sensitive rats, and during short-term artificial hyperglycemia in rats induced by intravenous glucose and octreotide. STZ-treated rats received insulin, the superoxide dismutase mimetic tempol, or contrast medium. Radiocontrast media causes hypoxia and HIF induction. Hypoxia, HIFs, and heme oxygenase were undetectable in controls, but transiently activated in STZ-treated and the Cohen diabetes sensitive rats. Different patterns of HIFs and pimonidazole were observed between the three models. Insulin abolished pimonidazole and HIF induction, whereas tempol lead to increased HIFs and heme oxygenase induction at similar levels of pimonidazole. When compared with control rats, STZ-treated rats exhibited more intense and protracted renal pimonidazole, with augmented hypoxia inducible factor production and reduced GFR following contrast media. Our data suggest that both regional hypoxia and hypoxia adaptation transiently occur in early stages of experimental diabetes, largely dependent on hyperglycemia or after contrast media. Tempol may augment the HIF response in diabetes.

CRBP-I in the renal tubulointerstitial compartment of healthy rats and rats with renal fibrosis

Katrien Van Beneden — 2008-05-30T04:25:51-00:00

Nephrol. Dial. Transplant. (25 May 2008), gfn290.

Background. Cellular retinol-binding proteins (CRBP-I), a member of the intracellular lipid-binding protein (iLBP) superfamily, is a specific marker of quiescent stellate cells in the healthy human liver. In the diseased fibrotic/cirrhotic liver, portal and septal myofibroblasts acquire CRBP-I expression, while activated hepatic stellate cells maintain their CRBP-I expression. Here, we investigate the distribution of CRBP-I in the renal cortex of healthy rats and rats with renal fibrosis. Methods. Kidneys of healthy and adriamycin-treated rats were studied by immunohistochemistry, using antibodies against CRBP-I, desmin, vimentin and alpha-smooth muscle actin (alpha-SMA). Double stainings were done with immunofluorescence. Western blotting was performed to semi-quantify the expression levels of vimentin, desmin, alpha-SMA and CRBP-I. Results. In the normal rat kidney, the convoluted proximal tubular epithelial cells express CRBP-I; no expression is found in the interstitium, nor in the glomeruli. In the adriamycin-induced fibrotic rat kidney, CRBP-I expression diminishes in the convoluted proximal tubular epithelial cells, whereas peritubular myofibroblasts in the interstitium acquire CRBP-I expression. Conclusions. In the tubulointerstitial compartment of the adriamycin-induced fibrotic rat kidney, CRBP-I is expressed in a different pattern than in the healthy rat kidney. As the convoluted proximal tubular epithelial cells dedifferentiate during fibrosis, CRBP-I expression decreases. Furthermore, de novo expression of CRBP-I is found in activated myofibroblast-like cells in the interstitium of adriamycin-treated rats. CRBP-I is therefore a useful marker to identify a subpopulation of activated/ myodifferentiated fibroblasts in the rat kidney. 10.1093/ndt/gfn290

Role of Advanced Glycation End Products With Oxidative Stress in Resistance Artery Dysfunction in Type 2 Diabetic Mice.

Jun Su — 2008-05-30T03:21:16-00:00

Arteriosclerosis, thrombosis, and vascular biology (15 May 2008)

OBJECTIVE: Type 2 diabetes is associated with increased advanced glycation end product (AGE) formation and vasculopathy. We hypothesized that AGEs contribute to resistance artery dysfunction. METHODS AND RESULTS: Type 2 diabetic db(-)/db(-) (diabetic) and nondiabetic db(-)/db(+) (control) mice were treated with the AGE inhibitor (aminoguanidine: 50 mg/Kg/d) for 3 months. Isolated mesenteric resistance arteries (MRAs) were mounted in an arteriograph. Pressure-induced myogenic tone (MT) was increased in diabetic mice but was unaffected by aminoguanidine treatment. Phenylephrine-induced contraction and nitric oxide donor-induced endothelium-independent relaxation were similar in all groups. In diabetic mice, endothelium-dependent relaxation in response to shear-stress or acetylcholine was altered and was associated with reduced eNOS protein and mRNA expression. Aminoguanidine treatment improved endothelial function and restored eNOS expression. AGE formation and hypoxia markers (plasminogen activator inhibitor 1 and Bnip3) were increased in MRA from diabetic mice and normalized with Aminoguanidine. Primary cultured endothelial cells (ECs) isolated from resistance arteries subjected to high glucose for 48 hours showed decreased eNOS expression and phosphorylation in response to calcium ionophore. High glucose decreased antioxidant protein (MnSOD) and increased prooxidant proteins (gp91phox) expression leading to increased oxidative stress generation, as assessed by DHE staining and endothelial NADH/NADPH oxidase activity. The preincubation of ECs with aminoguanidine restored eNOS-phosphorylation and expression as well as the balance between pro- and antioxidant factors induced by high glucose. CONCLUSIONS: We provide evidence of a link between AGEs, oxidative stress, and resistance artery EC dysfunction in type 2 diabetic mice. Thus, AGEs and oxidative stress may be a potential target for overcoming diabetic microvessels complications.

EuroPhenome and EMPReSS: online mouse phenotyping resource.

Ann-Marie Mallon — 2007-10-10T08:38:46-00:00

Nucleic Acids Res (28 September 2007)

EuroPhenome (http://www.europhenome.org) and EMPReSS (http://empress.har.mrc.ac.uk/) form an integrated resource to provide access to data and procedures for mouse phenotyping. EMPReSS describes 96 Standard Operating Procedures for mouse phenotyping. EuroPhenome contains data resulting from carrying out EMPReSS protocols on four inbred laboratory mouse strains. As well as web interfaces, both resources support web services to enable integration with other mouse phenotyping and functional genetics resources, and are committed to initiatives to improve integration of mouse phenotype databases. EuroPhenome will be the repository for a recently initiated effort to carry out large-scale phenotyping on a large number of knockout mouse lines (EUMODIC).

DigiPINS: A database for vertebrate exonic single nucleotide polymorphisms and its application to cancer association studies.

V Navratil — 2008-05-23T02:27:35-00:00

Biochimie, Vol. 90, No. 4. (April 2008), pp. 563-569.

Single nucleotide polymorphisms (SNPs), which are the most abundant form of genetic variations in numerous organisms, have emerged as important tools for the study of complex genetic traits and deciphering of genome evolution. High-throughput genome sequencing projects worldwide provide an unprecedented opportunity for whole-genome SNP analysis in a variety of species. To facilitate SNP discovery in vertebrates, we have developed a web-based, user-friendly, and fully automated application, DigiPINS, for genome-wide identification of exonic SNPs from EST data. Currently, the database can be used to the mining of exonic SNPs in six complete genomes (Homo sapiens, Mus musculus, Rattus norvegicus, Canis familiaris, Gallus gallus and Danio rerio). In addition to providing information on sequence conservation, DigiPINS allows compilation of comprehensive sets of polymorphisms within cancer candidate genes or identification of novel cancer markers, making it potentially useful for cancer association studies. The DigiPINS server is available via the internet at http://pbil.univ-lyon1.fr/gem/DigiPINS/query_DigiPINS.php.

Animal trait ontology: The importance and usefulness of a unified trait vocabulary for animal species.

LM Hughes — 2008-05-22T02:39:01-00:00

Journal of animal science, Vol. 86, No. 6. (June 2008), pp. 1485-1491.

Ontologies help to identify and formally define the entities and relationships in specific domains of interest. Bio-ontologies, in particular, play a central role in the annotation, integration, analysis, and interpretation of biological data. Missing from the number of bio-ontologies is one that includes phenotypic trait information found in livestock species. As a result, the Animal Trait Ontology (ATO) project being carried out under the auspices of the USDA-National Animal Genome Research Program is aimed at the development of a standardized trait ontology for farm animals and software tools to assist the research community in collaborative creation, editing, maintenance, and use of such an ontology. The ATO is currently inclusive of cattle, pig, and chicken species, and will include other livestock species in the future. The ATO will eventually be linked to other species (e.g., human, rat, mouse) so that comparative analysis can be efficiently performed between species.

Comprehensive and quantitative proteome profiling of the mouse liver and plasma.

KK Lai — 2008-05-20T04:30:49-00:00

Hepatology (Baltimore, Md.), Vol. 47, No. 3. (March 2008), pp. 1043-1051.

We report a comprehensive and quantitative analysis of the mouse liver and plasma proteomes. The method used is based on extensive fractionation of intact proteins, further separation of proteins based on their abundance and size, and high-accuracy mass spectrometry. This analysis reached a depth in proteomic profiling not reported to date for a mammalian tissue or a biological fluid, with 7099 and 4727 proteins identified with high confidence in the liver and in the corresponding plasma, respectively. This method allowed for the identification in both compartments of low-abundance proteins such as cytokines, chemokines, and receptors and for the detection in plasma of proteins in the pg/mL concentration range. This method also allowed for semiquantitation of all identified proteins. The calculated abundance scores correlated with the abundance of the corresponding transcripts for the large majority of the proteins identified in the liver. Finally, comparison of the liver and plasma datasets demonstrated that a significant number of proteins identified in the liver can be detected in plasma. These included proteins involved in complement and coagulation, in fatty acid, purine and pyruvate metabolism, in gluconeogenesis and glycolysis, in protein ubiquitination, and in insulin, interleukin-4, epidermal growth factor, and platelet-derived growth factor signaling. CONCLUSION: This in-depth analysis of the mouse liver and corresponding plasma proteomes provides a strong basis for investigations of liver pathobiology and biology that employ mouse models of hepatic diseases in an effort to better understand, diagnose, treat, and prevent human hepatic diseases.

Bioluminescence imaging of hollow fibers in living animals: its application in monitoring molecular pathways

Guo-Jun Zhang — 2008-05-20T03:52:12-00:00

Nat. Protocols, Vol. 3, No. 5. (May 2008), pp. 891-899.

Determination of plasma and urinary angiotensinogen levels in rodents by newly developed ELISA

Hiroyuki Kobori — 2008-05-02T10:12:41-00:00

Am J Physiol Renal Physiol, Vol. 294, No. 5. (1 May 2008), pp. F1257-1263.

We recently reported that urinary excretion rates of angiotensinogen provide a specific index of the intrarenal renin-angiotensin system status in angiotensin II-dependent hypertensive rats. Angiotensinogen concentrations in mouse plasma are thought to be much lower than those in rat plasma; however, detailed information is deficient due to lack of direct quantitative measurements of rodent angiotensinogen. To elucidate this issue, we have developed a quantitative method for measurement of rodent angiotensinogen using a sandwich-type ELISA. The standard curve for mouse and rat angiotensinogen exhibited a high linearity at 0.16-10 and 0.08-5 ng/ml, respectively, with correlation coefficients >0.99. While plasma angiotensinogen concentrations of male high serum IgA (HIGA) mice (IgA nephritis model animals, 1,308 +/- 47 ng/ml; n = 10) were lower than those of control BALB/c mice (1,620 +/- 384; n = 12), urinary angiotensinogen concentrations of HIGA mice (14.6 +/- 1.5 ng/ml; n = 34) were higher than those of BALB/c mice (4.6 +/- 0.1; n = 2). In a similar manner, while plasma angiotensinogen concentrations of Zucker diabetic fatty (ZDF) obese rats (type 2 diabetic model animals, 1,789 +/- 50 ng/ml; n = 5) were lower than those of control ZDF lean rats (2,296 +/- 47; n = 5), urinary angiotensinogen concentrations of ZDF obese rats (88.2 +/- 11.4 ng/ml; n = 15) were higher than those of ZDF lean rats (31.3 +/- 1.9; n = 15). These data indicate that plasma and urinary angiotensinogen concentrations are less in mice than rats. However, these data suggest that urinary angiotensinogen levels are different from plasma angiotensinogen levels in rodents. The development of rodent angiotensinogen ELISA allows quantitative comparisons in mouse and rat angiotensinogen levels in models of hypertension and cardiovascular and kidney diseases. 10.1152/ajprenal.00588.2007

Plasma creatinine determination in mice and rats: An enzymatic method compares favorably with a high-performance liquid chromatography assay

A Keppler — 2008-04-20T15:54:43-00:00

Kidney Int, Vol. 71, No. 1. (1 November 2006), pp. 74-78.

Can rodent models of diabetic kidney disease clarify the significance of early hyperfiltration?: recognizing clinical and experimental uncertainties.

DZ Levine — 2008-04-18T02:23:02-00:00

Clinical science (London, England : 1979), Vol. 114, No. 2. (January 2008), pp. 109-118.

In the past, hyperfiltration and increased glomerular capillary pressure have been identified as important determinants of the development of DN (diabetic nephropathy). Recently, some basic research and clinical reviews on DN have omitted identifying hyperfiltration as an important risk factor. At the same time, different rodent models of DN have been described without and with documented hyperfiltration. In the present review, the importance of hyperfiltration is reassessed, reviewing key clinical and research studies, including the first single nephron studies in a mouse model of DN. From clinical studies of Type 1 and Type 2 diabetes mellitus, it is clear that many patients do not have early hyperfiltration and, even when present, its contribution to subsequent DN remains uncertain. Key mechanisms underlying hyperfiltration in rodent models are reviewed. Findings on intrarenal NO metabolism and the control of single-nephron GFR (glomerular filtration rate) in rodent models of DN are also presented. Characterization of valid experimental models of DN should include a careful delineation of the absence or presence of early hyperfiltration, with special efforts made to establish the specific role hyperfiltration may play in the emergence of DN.

Renal Fibrosis and Glomerulosclerosis in a New Mouse Model of Diabetic Nephropathy and its Regression by BMP-7 and Advanced Glycation End-Product Inhibitors.

Hikaru Sugimoto — 2007-06-13T09:35:10-00:00

Diabetes (24 April 2007)

Diabetic nephropathy is currently the most common cause of end-stage renal disease (ESRF) in the western world. A mouse model for diabetic nephropathy that encompasses the salient features of this disease in the kidney is not available. Here, we report that CD1 mice, in contrast to inbred C57BL/6 and 129sv strains, develop ESRF associated with prominent tubulointerstitial nephritis and fibrosis within three months and die due to diabetic complication by 6-7 months after a single injection of streptozotocin. Histopathologic lesions observed in these mice mimic human diabetic nephropathy including glomerular hypertrophy, diffuse glomerulosclerosis, tubular atrophy, interstitial fibrosis and decreased renal excretory function. Next, we tested the therapeutic efficacy of bone morphogenic protein-7 (BMP-7) and inhibitors of advanced glycation end-products (AGE), aminoguanidine and pyridoxamine, to inhibit and regress the progression of renal disease in diabetic CD1 mice. We demonstrate that while aminoguanidine, pyridoxamine and BMP-7 significantly inhibit glomerular lesions, BMP-7 is most effective in the inhibition of tubular inflammation and tubulointerstitial fibrosis in these mice. Collectively, our results report a new mouse model for diabetic nephropathy with prominent interstitial inflammation and fibrosis and the selective inhibition of diabetic kidney disease by AGE inhibitors and BMP-7.

Gene expression profile in streptozotocin-induced diabetic mice kidneys undergoing glomerulosclerosis

Jun Wada — 2008-03-22T10:35:05-00:00

Kidney Int, Vol. 59, No. 4. (April 2001), pp. 1363-1373.

Animal models of human diseases-Taiwan

2008-03-22T08:02:30-00:00

Late Onset of Ccl2 Blockade with the Spiegelmer mNOX-E36-3'PEG Prevents Glomerulosclerosis and Improves Glomerular Filtration Rate in db/db Mice.

V Ninichuk — 2008-03-22T02:45:53-00:00

Am J Pathol, Vol. 172, No. 3. (March 2008), pp. 628-637.

Diabetic kidney disease is associated with monocyte chemoattractant CC chemokine ligand 2 (CCL2)-dependent glomerular and interstitial macrophage recruitment. In addition, nephropathy is delayed in Ccl2 mutant diabetic mice. However, whether the late onset of therapeutic Ccl2 blockade modulates the progression of advanced diabetic nephropathy remains unknown. We addressed this question by antagonizing Ccl2 with mNOX-E36-3'PEG, an anti-Ccl2 L-enantiomeric RNA aptamer (ie, a Spiegelmer), which binds murine Ccl2 and blocks the recruitment of ex vivo-labeled macrophages to the kidneys of db/db mice with type 2 diabetes. We injected mNOX-E36-3'PEG subcutaneously at a dose of 50 mg/kg three times per week into uninephrectomized (1K) db/db mice with advanced glomerulopathy from 4 to 6 months of age. mNOX-E36-3'PEG reduced the number of glomerular macrophages by 40% compared with nonfunctional (control) Spiegelmer-treated 1K db/db mice. This result was associated with protection from diffuse glomerulosclerosis and significantly improved the glomerular filtration rate. mNOX-E36-3'PEG also reduced renal Ccl2 mRNA and protein expression compared with control Spiegelmer-treated 1K db/db mice of the same age. Together, the late onset of therapeutic Ccl2 blockade, eg, with specific Spiegelmers, offers protection from diffuse glomerulosclerosis in type 2 diabetic db/db mice and, thus, may represent a novel therapeutic strategy for advanced glomerulosclerosis.

Characterization of diabetic nephropathy in a transgenic model of hypoinsulinemic diabetes.

Y Kanetsuna — 2007-09-04T05:01:54-00:00

Am J Physiol Renal Physiol, Vol. 291, No. 6. (December 2006)

Genetic mouse models provide a unique opportunity to investigate gene function in the natural course of the disease. Although diabetic nephropathy (DN) in models of type II diabetes has been well characterized, diabetic renal disease in hypoinsulinemic diabetic mice is still incompletely understood. Here, we characterized renal changes in the pdx1(PB)-HNF6 transgenic mouse that exhibits beta-cell dysfunction and nonobese hypoinsulinemic diabetes. Male transgenic mice developed hyperglycemia by the age of 7 wk and survived for over 1 yr without insulin treatment. Diabetes ensued earlier and progressed more severely in the HNF6 males than the females. The HNF6 males exhibited albuminuria as early as 10 wk of age, and the urinary albumin excretion increased with age, exceeding 150 microg/24 h at 11 mo of age. Diabetic males developed renal hypertrophy after 7 wk of age, whereas glomerular hyperfiltration was not observed in the mice. Hypertension and hyperlipidemia were not observed in the diabetic mice. Histological analysis of the HNF6 kidneys displayed diabetic glomerular changes, including glomerular enlargement, diffuse mesangial proliferation and matrix expansion, thickened glomerular basement membrane, and arteriolar hyalinosis. Mesangial matrix accumulation increased with age, resulting in nodular lesions by 44 wk of age. Immunohistochemistry showed accumulation of type IV collagen and TGF-beta1 in the mesangial area. No significant immune complex deposition was observed in the HNF6 glomeruli. Thus the HNF6 mouse exhibits diabetic renal changes that parallel the early phase of human DN. The model should facilitate studies of genetic and environmental factors that may affect DN in hypoinsulinemic diabetes.

The rat model of type 2 diabetic mellitus and its glycometabolism characters.

F Zhang — 2008-03-22T01:05:37-00:00

Exp Anim, Vol. 52, No. 5. (October 2003), pp. 401-407.

To develop a rat model of type 2 diabetic mellitus that simulated the common manifestation of the metabolic abnormalities and resembled the natural history of a certain type 2 diabetes in human population, male Sprague-Dawley rats (4 months old) were injected with low-dose (15 mg/kg) STZ after high fat diet (30% of calories as fat) for two months (L-STZ/2HF). The functional and histochemical changes in the pancreatic islets were examined. Insulin-glucose tolerance test, islet immunohistochemistry and other corresponding tests were performed and the data in L-STZ/2HF group were compared with that of other groups, such as the model of type 1 diabetes (given 50 mg/kg STZ) and the model of obesity (high fat diet). The body weight of rats in the group of rats given 15 mg/kg STZ after high fat diet for two months increased significantly more than that of rats in the group of rats given 50 mg/kg STZ (the model of type 1 diabetes) (595 +/- 33 g vs. 352 +/- 32 g, p<0.05). Fast blood glucose levels for L-STZ/2HF group were 16.92 +/- 1.68 mmol/l, versus 5.17 +/- 0.55 mmol/l in normal control and 5.59 +/- 0.61 mmol/l in rats given high fat diet only. Corresponding values for fast serum insulin were 0.66 +/- 0.15 ng/ml, 0.52 +/- 0.13 ng/ml, 0.29 +/- 0.11 ng/ml, respectively. Rats of type 2 diabetes (L-STZ/2HF) had elevated levels of triglyceride (TG, 3.82 +/- 0.88 mmol/l), and cholesterol(Ch, 2.38 +/- 0.55 mmol/l) compared with control (0.95 +/- 0.15 mmol/l and 1.31 +/- 0.3 mmol/l, respectively) (p<0.05). The islet morphology as examined by immunocytochemistry using insulin antibodies in the L-STZ/2HF group was affected and quantitative analysis showed the islet insulin content was higher than that of rats with type 1 diabetes (P<0.05). We concluded that the new rat model of type 2 diabetes established with conjunctive treatment of low dose of STZ and high fat diet was characterized by hyperglycemia and light impaired insulin secretion function accompanied by insulin resistance, which resembles the clinical manifestation of type 2 diabetes. Such a model, easily attainable and inexpensive, would help further elucidation of the underlying mechanisms of diabetes and its complications.

Establishment and pathophysiological characterization of type 2 diabetic mouse model produced by streptozotocin and nicotinamide.

T Nakamura — 2008-03-22T00:52:32-00:00

Biol Pharm Bull, Vol. 29, No. 6. (June 2006), pp. 1167-1174.

This study was performed in order to establish a mouse model that represents the non-obese type 2 diabetes reflecting a majority of diabetic patients among Asian races and to show its pathophysiological profiles. Streptozotocin (STZ) was administered to C57BL/6J mice with or without nicotinamide (120 or 240 mg/kg, STZ/NA120 or STZ/NA240), twice with an interval of 2 d, and plasma glucose concentration, body weight, water intake, insulin contents and insulin signal-related proteins were monitored. STZ-induced hyperglycemia (fasting and non-fasting), body weight loss and polyposia were significantly depressed by NA dose-dependently. In STZ/NA120 and STZ/NA240 mice, pancreatic insulin content was retained by 28 and 43% of normal control (10.5+/-0.93 muU/ml), respectively, and histological damage of pancreatic beta cells was also less severe than that observed in STZ mice. When given the calorie-controlled high fat diet, the STZ/NA mice caused hyperlipidemia, and significantly increased insulin resistance. These observations suggest that the combined administration of STZ and NA causes partial depletion of pancreatic insulin and that the high fat constituents lead to insulin resistance in this model. The present mouse model, therefore, well exhibits the recent diabetic pathophysiological characteristics of a majority of Asian patients.

An imputed genotype resource for the laboratory mouse.

Jin Szatkiewicz — 2008-03-15T03:37:30-00:00

Mamm Genome (27 February 2008)

We have created a high-density SNP resource encompassing 7.87 million polymorphic loci across 49 inbred mouse strains of the laboratory mouse by combining data available from public databases and training a hidden Markov model to impute missing genotypes in the combined data. The strong linkage disequilibrium found in dense sets of SNP markers in the laboratory mouse provides the basis for accurate imputation. Using genotypes from eight independent SNP resources, we empirically validated the quality of the imputed genotypes and demonstrated that they are highly reliable for most inbred strains. The imputed SNP resource will be useful for studies of natural variation and complex traits. It will facilitate association study designs by providing high-density SNP genotypes for large numbers of mouse strains. We anticipate that this resource will continue to evolve as new genotype data become available for laboratory mouse strains. The data are available for bulk download or query at http://cgd.jax.org /.

Techniques of animal experiment in Taiwan

2008-03-12T04:01:10-00:00

A model for diabetic nephropathy: Advantages of the inducible cAMP early repressor transgenic mouse over the streptozotocin-induced diabetic mouse.

Akari Inada — 2008-02-24T05:54:04-00:00

J Cell Physiol, Vol. 215, No. 2. (12 February 2008), pp. 383-391.

We have previously found progressive diabetic nephropathy in inducible cAMP early repressor (ICER Igamma) transgenic (Tg) mice. The ICER Igamma Tg mouse is an interesting model of sustained hyperglycemia due to its low production of insulin and insulin-producing beta cells. Here in a longitudinal study we further analyzed diabetic nephropathy and structural and functional alterations in other organs, comparing our model with streptozotocin (STZ)-diabetic model mice. The high-dose STZ-diabetic model showed marked variation in blood glucose levels and severe toxicity of STZ in the liver and kidney. The low-dose STZ-diabetic model showed less toxicity, but the survival rate was very low. STZ-diabetic mice had much more variation of glomerular hypertrophy and sclerosis. Furthermore, non-specific toxicity of STZ or insulin injections to maintain optimal blood glucose levels might have another effect upon the diabetic renal changes. In contrast, ICER Igamma Tg mice exhibited a stable and progressive phenotype of diabetic kidney disease solely due to chronic hyperglycemia without other modulating factors. Thus, ICER Igamma Tg mouse has advantages for examining diabetic renal disease, and offers unique and very different perspectives compared to STZ model. J. Cell. Physiol. 215: 383-391, 2008. (c) 2008 Wiley-Liss, Inc.

A novel class of advanced glycation inhibitors ameliorates renal and cardiovascular damage in experimental rat models

Yuko Izuhara — 2008-02-11T09:36:21-00:00

Nephrol. Dial. Transplant., Vol. 23, No. 2. (1 February 2008), pp. 497-509.

Background. The reno- and cardiovascular-protective effects of angiotensin II receptor blockers (ARBs), have been ascribed, at least in part, to their ability to inhibit the formation of advanced glycation end products (AGEs), independently of their effect on blood pressure. They act through decreased oxidative stress, unlike previously reported AGE inhibitors which entrap reactive carbonyl (RCOs) precursors of AGEs. The hypotensive effects of ARBs', however, may limit their use. In the present study, we report the synthesis of a new AGE inhibitor, TM2002, and its effects in vitro and in vivo. Methods. We screened a large chemical library ([~]1300 compounds) including edaravone, a drug used to treat cerebral infarction, for in vitro AGE inhibitory activity. Based upon the structure-function analysis of edaravone derivatives, we synthesized a novel AGE inhibitor, 1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-6-methyl-1,3-dihydro-furo[3,4-c]pyridine-7-ol (TM2002). We delineate in vitro the biological characteristics of TM22002, evaluate in vivo its toxico-pharmacokinetics and document in animal models of rat, their renal and cardiovascular protective effectiveness. Results. Screening of a large chemical library disclosed that edaravone inhibits in vitro AGE formation efficiently. Unfortunately, like most AGE inhibitors, it also traps pyridoxal, limiting its clinical usefulness. We therefore synthesized a novel AGE inhibitor, TM2002, that does not trap pyridoxal. In vitro, TM2002 shows powerful AGE inhibitory activity. Markers of oxidation, i.e. o-tyrosine formation and transition metal chelation, are efficiently inhibited by TM2002-like ARBs. TM2002 does not bind to the angiotensin II type 1 receptor. It is readily bioavailable and non-toxic. In vivo, TM2002, given acutely or for 8 weeks, has no adverse effects. In four different rat models of renal injury (anti-Thy1 and ischaemia-reperfusion) and cardiovascular injury (carotid artery balloon injury and angiotensin II-induced cardiac fibrosis), TM2002 improves renal and cardiovascular lesions without modification of blood pressure. Conclusions. TM2002 is a novel, non-toxic AGE inhibitor acting through ARB-like mechanisms, able to prevent renal and cardiovascular diseases independently of blood pressure lowering. 10.1093/ndt/gfm601

Insight into the genetics of diabetic nephropathy through the study of mice.

MD Breyer — 2007-12-31T05:15:18-00:00

Curr Opin Nephrol Hypertens, Vol. 17, No. 1. (January 2008), pp. 82-86.

PURPOSE OF REVIEW: To discuss mouse models of diabetic nephropathy and their use in discovering genetic risk factors predisposing to diabetic nephropathy. RECENT FINDINGS: Despite occurring in only 10-40% of diabetic patients, diabetic nephropathy is the largest single cause of end stage renal disease in the USA. Accumulated evidence points to critical genetic factors that predispose a subset of diabetic patients to nephropathy.Defining the genes that confer risk for nephropathy in human populations has proven challenging. The use of robust genetic reagents available in the laboratory mouse provides a complementary approach to defining genes that predispose to diabetic nephropathy in mice and humans. These findings support the existence of dominant mutations predisposing to diabetic nephropathy in mice as well as substantiating an important role for eNOS in forestalling the development of diabetic nephropathy. SUMMARY: When studied for a sufficient duration of diabetic hyperglycemia, some strains of mice exhibit changes similar to those of human diabetic nephropathy. The unique genetic reagents in mice should help accelerate the identification of genes predisposing to diabetic nephropathy.

Pitavastatin ameliorates albuminuria and renal mesangial expansion by downregulating NOX4 in db/db mice.

M Fujii — 2007-10-21T14:14:01-00:00

Kidney Int, Vol. 72, No. 4. (August 2007), pp. 473-480.

Recent studies have uncovered various pleiotrophic effects of 3-hydroxy-3-methylglutaryl coenzyme A reductase-inhibiting drugs (statins). Several studies have identified a beneficial effect of statins on diabetic nephropathy; however, the molecular mechanisms are unclear. In this study, we show that statin ameliorates nephropathy in db/db mice, a rodent model of type 2 diabetes, via downregulation of NAD(P)H oxidase NOX4, which is a major source of oxidative stress in the kidney. Pitavastatin treatment for 2 weeks starting at 12 weeks of age significantly reduced albuminuria in the db/db mice concomitant with a reduction of urinary 8-hydroxy-2'-deoxyguanosine and 8-epi-prostaglandin F(2alpha). Immunohistochemical analysis found increased amounts of 8-hydroxy-2'-deoxyguanosine and NOX4 protein in the kidney of db/db mice. Quantitative reverse transcription-polymerase chain reaction also showed increased levels of NOX4 mRNA. Pitavastatin normalized all of these changes in the kidneys of diabetic animals. Additionally, 12-week treatment with the statin completely normalized the levels of transforming growth factor-beta1 and fibronectin mRNA as well as the mesangial expansion characteristic of diabetic nephropathy. Our study demonstrates that pitavastatin ameliorates diabetic nephropathy in db/db mice by minimizing oxidative stress by downregulating NOX4 expression. These findings may provide insight into the mechanisms of statin therapy in early stages of diabetic nephropathy.

Tubular atrophy, interstitial fibrosis, and inflammation in type 2 diabetic db/db mice. An accelerated model of advanced diabetic nephropathy.

V Ninichuk — 2007-10-21T13:59:39-00:00

Eur J Med Res, Vol. 12, No. 8. (16 August 2007), pp. 351-355.

OBJECTIVE: Advanced diabetic nephropathy (DN) is difficult to address experimentally in mice because available models of DN lack global glomerulosclerosis and major tubulointerstitial pathology. Accelerating the development of DN in mice would be desirable for feasible experimental validation of potential targets that mediate the progression to late stage DN. METHODS: 6 week old male db/db mice underwent uninephrectomy and the development of nephropathy was compared to wild-type mice and sham-operated db/db mice. RESULTS: Uninephrectomy at young age was associated with increased albuminuria and severe glomerulosclerosis in 37% of glomeruli at 24 weeks of age as compared to sham-operated db/db mice (8%). Uninephrectomy also increased the number of glomerular macrophages in db/db mice. The uninephrectomy-related acceleration of glomerular damage was associated with significant tubulointerstitial injury as indicated by an increase in indices of tubular cell damage, tubular dilatation, and expansion of interstitial volume. Uninephrectomy markedly increased the renal mRNA expression of Mcp-1/Ccl2, Tgf-beta, and collagen I. CONCLUSION: Early uninephrectomy can accelerate the development of advanced DN in db/db mice which may be instrumental in the design of interventional studies that intend to focus on the molecular pathology of the progression to late stage DN.

Role of Altered Renal Lipid Metabolism in the Development of Renal Injury Induced by a High-Fat Diet

Shinji Kume — 2007-10-01T15:59:13-00:00

J Am Soc Nephrol, Vol. 18, No. 10. (1 October 2007), pp. 2715-2723.

Metabolic syndrome is associated with increased risk of chronic kidney disease, and the renal injury in patients with metabolic syndrome may be a result of altered renal lipid metabolism. We fed wild-type or insulin-sensitive heterozygous peroxisome proliferatoractivated receptor gammadeficient (PPARgamma+/) mice a high-fat diet for 16 weeks. In wild-type mice, this diet induced core features of metabolic syndrome, subsequent renal lipid accumulation, and renal injury including glomerulosclerosis, interstitial fibrosis, and albuminuria. Renal lipogenesis accelerated, determined by increased renal mRNA expression of the lipogenic enzymes fatty acid synthase and acetyl-CoA carboxylase (ACC) and by increased ACC activity. In addition, renal lipolysis was suppressed, determined by reduced mRNA expression of the lipolytic enzyme carnitine palmitoyl acyl-CoA transferase 1 and by reduced activity of AMP-activated protein kinase. In PPARgamma+/ mice, renal injury, systemic metabolic abnormalities, renal accumulation of lipids, and the changes in renal lipid metabolism were attenuated. Thus, a high-fat diet leads to an altered balance between renal lipogenesis and lipolysis, subsequent renal accumulation of lipid, and renal injury. We suggest that renal lipid metabolism could serve as a new therapeutic target to prevent chronic kidney disease in patients with metabolic syndrome. 10.1681/ASN.2007010089

Differentiating between effects of streptozotocin per se and subsequent hyperglycemia on renal function and metabolism in the streptozotocin-diabetic rat model.

F Palm — 2007-09-04T05:03:06-00:00

Diabetes Metab Res Rev, Vol. 20, No. 6. (c 2004), pp. 452-459.

BACKGROUND: The animal model with streptozotocin (STZ)-induced diabetes mellitus is associated with progressive renal disturbances. The aim of this study was to differentiate between toxic effects of STZ and the effect of hyperglycemia. Previous studies have been limited to investigating the influence of STZ on glomerular filtration rate (GFR), albuminuria and renal morphology. The present study presents a new approach when transplanting beta-cells to cure the STZ-treated animals and extends the evaluation to include both renal function and oxygen metabolism. METHODS: Animals were allocated to three groups: control animals, STZ-diabetic animals and animals rendered diabetic with an injection of STZ, followed by immediate syngeneic transplantation of approximately 1000 pancreatic islets into the splenic parenchyma. This latter procedure reversed the hyperglycemia induced by STZ. Renal function was evaluated from GFR and urinary albumin and protein leakage, while regional renal blood flow was determined using a laser-Doppler technique and oxygen tension measured with Clark-type electrodes. RESULTS: In diabetic animals, GFR increased, renal oxygen tension decreased and renal hypertrophy occurred, along with urinary leakage of protein, including albumin. Early transplantation of pancreatic islets to STZ-treated animals prevented the development of all these changes, except for proteinuria. However, an analysis of urinary protein content revealed that albuminuria was preventable by islet transplantation. CONCLUSIONS: We conclude that the urinary protein leakage in this animal model is at least partly due to direct toxic effects of STZ, whereas the other renal changes investigated in this study are due to the long-term diabetic condition.

Combination therapy with an Angiotensin-converting enzyme inhibitor and a vitamin d analog suppresses the progression of renal insufficiency in uremic rats.

M Mizobuchi — 2007-08-29T07:21:43-00:00

J Am Soc Nephrol, Vol. 18, No. 6. (June 2007), pp. 1796-1806.

Monotherapy with angiotensin-converting enzyme inhibitors has been shown to be beneficial in suppressing the progression of experimentally induced kidney diseases. Whether such therapy provides additional benefits when combined with vitamin D or an analog of vitamin D has not been established. Rats were made uremic by 5/6 nephrectomy and treated as follows: Uremic + vehicle (UC), uremic + enalapril (30 mg/L in drinking water; E), uremic + paricalcitol (19-nor; 0.8 mug/kg, three times a week), and uremic + enalapril + paricalcitol (E + 19-nor). A group of normal rats served as control (NC). BP was significantly elevated in the UC and 19-nor groups compared with the NC group but was indistinguishable from normal in the E and E + 19-nor groups. The decrease in creatinine clearance and the increase in the excretion of urinary protein that were observed in the UC group were ameliorated by the use of E alone or by E + 19-nor (P < 0.05 versus UC). The glomerulosclerotic index was significantly decreased in both the 19-nor (P < 0.01) and E + 19-nor groups (P < 0.01) compared with the UC group. Tubulointerstitial volume was significantly decreased in both the E (P < 0.05) and E + 19-nor groups (P < 0.01) compared with the UC group. Both macrophage infiltration (ED-1-positive cells) and production of the chemokine monocyte chemoattractant protein-1 were significantly blunted in E + 19-nor compared with E group. TGF-beta1 mRNA and protein expression were increased in the UC group (mRNA: 23.7-fold; protein: 29.1-fold versus NC). These increases were significantly blunted in the 19-nor group (mRNA: 7.1-fold; protein: 8.0-fold versus NC) and virtually normalized in the E + 19-nor group (protein: 0.8-fold versus NC). Phosphorylation of Smad2 was also elevated in the UC group (7.6-fold versus NC) but less so in the 19-nor-treated rats (5.5-fold versus NC). When rats were treated with E + 19-nor, the phosphorylation of Smad2 was normal (1.1-fold versus NC). Thus, 19-nor can suppress the progression of renal insufficiency via mediation of the TGF-beta signaling pathway, and this effect is amplified when BP is controlled via renin-angiotensin system blockade.

Renoprotective effects of a selective estrogen receptor modulator, raloxifene, in an animal model of diabetic nephropathy.

A Dixon — 2007-08-11T15:39:51-00:00

Am J Nephrol, Vol. 27, No. 2. (2007), pp. 120-128.

BACKGROUND/AIMS: Our previous studies have shown that supplementation with 17beta-estradiol (E2) from the onset of diabetes attenuates diabetic nephropathy. However, E2 is accompanied by feminizing effects as well as adverse side effects on other organs. The current study examined the renoprotective effects of a selective estrogen receptor modulator, raloxifene (RAL), in an experimental model of diabetic nephropathy. RAL activates estrogen receptors and estrogen-receptor-mediated cellular events without the side effects of E2. METHODS: The study was performed in Sprague-Dawley nondiabetic (ND), streptozotocin-induced diabetic (D) and streptozotocin-induced D + RAL rats (n = 6/group). RESULTS: After 12 weeks of treatment, D was associated with increased urine albumin excretion (ND: 4.2 +/- 0.4; D: 41.3 +/- 9.0 mg/day), glomerulosclerosis [glomerulosclerotic index; ND: 0.26 +/- 0.04; D: 1.86 +/- 0.80 arbitrary units (AU)], tubulointerstitial fibrosis (tubulointerstitial fibrosis index; ND: 0.37 +/- 0.05; D: 2.12 +/- 0.50 AU), increased collagen type I [ND: 1.31 +/- 0.07; D: 4.65 +/- 0.09 relative optical density (ROD)], collagen type IV (ND: 0.64 +/- 0.03; D: 1.37 +/- 0.11 ROD) and transforming growth factor beta (TGF-beta) protein expression (ND: 0.65 +/- 0.08; D: 1.25 +/- 0.10 ROD), increased density of CD68-positive cells (ND: 1.37 +/- 3.02; D: 29.2 +/- 1.74 cells/mm2) and increased plasma levels of interleukin-6 (ND: 14.8 +/- 5.0; D: 51.3 +/- 14.0 pg/ml). Treatment with RAL partially or fully attenuated these processes (urine albumin excretion: 21.0 +/- 5.0 mg/day; glomerulosclerotic index: 0.40 +/- 0.06 AU; tubulointerstitial fibrosis index: 0.20 +/- 0.04 AU; collagen type I: 2.55 +/- 0.49 ROD; collagen type IV: 0.70 +/- 0.09 ROD; TGF-beta: 0.91 +/- 0.08 ROD; CD68: 6.03 +/- 2.38 cells/mm2; interleukin-6: 31.2 +/- 5.0 pg/ml). CONCLUSIONS: Our data indicate that treatment with RAL attenuates albuminuria and renal structural changes associated with diabetes.

Arkadia-Smad7-mediated positive regulation of TGF-beta signaling in a rat model of tubulointerstitial fibrosis.

FY Liu — 2007-07-25T01:16:11-00:00

Am J Nephrol, Vol. 27, No. 2. (2007), pp. 176-183.

BACKGROUND/AIMS: Upregulation of transforming growth factor beta (TGF-beta)/Smad signaling has been implicated in the primary pathogenesis of renal fibrosis. The ubiquitin-proteasome pathway has an important influence on TGF-beta signaling through regulating Smad degradation. As E3 ubiquitin ligases, both Arkadia and Smurf2 are involved in this prosess. In this study, we focused on Arkadia, Smurf2, Smad7, and TGF-beta type I receptor (TbetaRI), principal molecules in the regulation of TGF-beta signaling, to understand the regulatory mechanism of ubiquitin-proteasomal degradation of TGF-beta signaling in the pathogenesis of renal fibrosis. METHODS: A unilateral ureteral obstruction (UUO) model was employed, and sham-operated rats were used as controls. Renal lesions and the expression of Arkadia, Smurf2, Smad7, TbetaRI, TGF-beta1, and type 1 collagen (COL-1) were detected by Western blot, immunoprecipitation, immunohistochemistry, and/or reverse transcription-polymerase chain reaction. RESULTS: The results indicated progressive tubulointerstitial fibrosis, high expression levels of Arkadia, Smurf2, TbetaRI, TGF-beta1 mRNA, type 1 collagen mRNA, and Smad7 mRNA, and low levels of Smad7 protein in the kidneys of rats with unilateral ureteral obstruction, in which Smurf2 interacted with both Smad7 and TbetaRI, and Arkadia only interacted with Samd7 but not with TbetaRI. CONCLUSION: Reduction of Smad7 resulting from ubiquitin-dependent degradation may be mainly attributed to Arkadia, and Arkadia-Smad7-mediated positive regulation of TGF-beta signaling may play a promoting role in the progression of tubulointerstitial fibrosis.

Combination of high-fat diet-fed and low-dose streptozotocin-treated rat: a model for type 2 diabetes and pharmacological screening.

K Srinivasan — 2007-07-05T02:22:06-00:00

Pharmacol Res, Vol. 52, No. 4. (October 2005), pp. 313-320.

The objective of the present study was to develop a rat model that replicates the natural history and metabolic characteristics of human type 2 diabetes and is also suitable for pharmacological screening. Male Sprague-Dawley rats (160-180 g) were divided into two groups and fed with commercially available normal pellet diet (NPD) (12% calories as fat) or in-house prepared high-fat diet (HFD) (58% calories as fat), respectively, for a period of 2 weeks. The HFD-fed rats exhibited significant increase in body weight, basal plasma glucose (PGL), insulin (PI), triglycerides (PTG) and total cholesterol (PTC) levels as compared to NPD-fed control rats. Besides, the HFD rats showed significant reduction in glucose disappearance rate (K-value) on intravenous insulin glucose tolerance test (IVIGTT). Hyperinsulinemia together with reduced glucose disappearance rate (K-value) suggested that the feeding of HFD-induced insulin resistance in rats. After 2 weeks of dietary manipulation, a subset of the rats from both groups was injected intraperitoneally with low dose of streptozotocin (STZ) (35 mg kg(-1)). Insulin-resistant HFD-fed rats developed frank hyperglycemia upon STZ injection that, however, caused only mild elevation in PGL in NPD-fed rats. Though there was significant reduction in PI level after STZ injection in HFD rats, the reduction observed was only to a level that was comparable with NPD-fed control rats. In addition, the levels of PTG and PTC were further accentuated after STZ treatment in HFD-fed rats. In contrast, STZ (35 mg kg(-1), i.p.) failed to significantly alter PI, PTG and PTC levels in NPD-fed rats. Thus, these fat-fed/STZ-treated rats simulate natural disease progression and metabolic characteristics typical of individuals at increased risk of developing type 2 diabetes because of insulin resistance and obesity. Further, the fat-fed/STZ-treated rats were found to be sensitive for glucose lowering effects of insulin sensitizing (pioglitazone) as well as insulinotropic (glipizide) agents. Besides, the effect of pioglitazone and glipizide on the plasma lipid parameters (PTG and PTC) was shown in these diabetic rats. The present study represents that the combination of HFD-fed and low-dose STZ-treated rat serves as an alternative animal model for type 2 diabetes simulating the human syndrome that is also suitable for testing anti-diabetic agents for the treatment of type 2 diabetes.

Rodent models of streptozotocin-induced diabetic nephropathy (Methods in Renal Research)

Greg Tesch — 2007-05-11T16:16:07-00:00

Nephrology, Vol. 12, No. 3. (June 2007), pp. 261-266.