| Objective: Peroxisome proliferator activated receptor-gamma (PPARγ) is a novel nuclear receptor is a ligand-regulated transcription factor that control genes expression by binding to specific response elements (PPREs) within the promoter's region of target genes, thereby regulating their transcription. New oral anti-diabetic agents, thiazolidinediones (TZDs) are recognized as highly selective synthetic ligands for the PPARgamma. Recent evidence shows that PPARγ agonists- TZDs have several metabolic regulation roles such as ameliorating hyperglycemia and dyslipidemia, improving insulin resistance and lowering blood pressure. Moreover, they also exert many non-metabolic functions like anti-inflammatory and anti-fibrotic effects. In kidney disease, TZDs show protective effects on both diabetic and non-diabetic rats subjected to 5/6 nephrectormy in term of progressive glomerulosclerosis without evidence of improvement of glucose metabolism. The action of PPARγ or TZDs on renal tubulointerstitial inflammation and fibrosis is not reported until now though its anti-inflammatory effects are known recently. Unilateral ureteral obstruction (UUO) is a model to induce renal tubulointerstitial inflammatory lesion and TNFα is a major cytokine to stimulate the inflammation, so we use rat UUO model and TNFα-stimulated IMCD model, from in vivo and in vitro, to clarify whether TZDs (rosiglitazone or pioglitazone) and PPARγ pathway present anti-inflammatory and anti-fibrotic effects, and their possible mechanisms. Our study demonstrated that PPARγ does involve in renal tubulointerstitial inflammatory process, and TZDs exhibit a good effect on ameliorating this process. Methods:1. In vivo study (UUO model). Adult male Sprague-Dawley rats were randomly divided into five groups, each group was subdivided into sub-groups (6 for each) according to different time point: (l)Sham-operated group (Sham): rat after sham operation 14d. (2)Sham-operated rats treated with rosiglitazone (30mg-kg-1 d-1) group(Sham+RSG) which were farther subdivided into Sham+RSG-3d, Sham+RSG-7d and Sham+RSG-14d three subgroups. (3)UUO vehicle group (UUO) subdivided into UUO3d, UUO7d, UUO14d. (4)UUO rats treated with rosiglitazone (Smg-kg'-d'1) (UUO+RSG1) subdivided into UUO+RSGl-3d, UUO+RSGl-7d and UUO+ RSGl-14d. (5)UUO rats treated with rosiglitazone ( SOmg-kg^-d'1 ) (UUO+RSG2) subdivided into UUO+RSG2-3d, UUO+RSG2-7d and UUO+RSG2-14d. Rosiglitazone was suspended in 0. 75% raethylcellulose solution, given 48hr before operation day by daily gavage. Non-drug treatment groups received equal volume of the solution instead of rosiglitazone. Animals were sacrificed at each intervention time point. Experimental observation was designed including several aspects: (lVTo observe RSG effect on UUO model: including animal model general information and serum indexes (like glucose, triglyceride, Cholesterol, blood uria nitrogen and creatinine), PAS and Masson trichrome staining to detect tubulointerstitial injury grade and the fibrosis index, and immunohistochemistry staining of ED-1 positive cell which indicated renal tissue macrophage infiltration. (2)To detection the mechanism of RSG's action. (1)The index relative with anti-inflammation aspect: including RT-PCR semi-quantitive method to evaluate obstructive renal cortex MCP-1 , TNFα, M-CSF mRNA level; ELISA kit to detect obstructive renal cortex MCP-1 protein level. (2)The mechanisms of RSG anti-fibotic effect. Renal α-SMA(representative of renal tubular epithelial cell transdifferentiated to myofibroblast) and pro-fibrotic factor TGF-βi expression was compared by using immunohistochemistry staining method, RT-PCR semi-quantitive method was used to evaluate obstructive renal cortex fibrosis relative indexes like TGF-β1, CTGF,. BMP-7 and Smad6 mRNA expression. ELISA way was used to measure renal cortex TGF-β1 protein levels. And western blotting was used to measure renal cortex pro-fibrotic protein PAI-1 and anti-fibrotic protein BMP-7 level. (3)Role on oxidative stress: Chemical c...
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