Protective Effects Of Rosiglitazone On Aortic Endothelial Function In Insulin Resistant Rats And Mechanism

Aims To investigate the protective effect of rosiglitazone (RSG) on aortic endothelial function of insulin resistant (IR) rats and the underlying mechanism.Methods Male SD rats were fed with high fructose diet for 4 weeks to induce IRrats model. To verify IR rats model, the following indexes were measured respectively in each group: Systolic blood pressure (SBP) were measured after fasting overnight, subsequently, blood samples were withdrawn from the end of tails of animals for fasting blood glucose (FBG), fasting serum insulin (FSI) at the end of weeks 0 ,2,4,6,8. and insulin sensitive index (ISI) were calculated. Control group rats were fed with common diet. After 4 weeks, rats were treated with or without rosiglitazone (5mg.Kg^-1.d¹ dissolved in water) for 4 weeks., At the end of 8th week, intraperitoneoclysis glucose tolerance test (IPGTT) insulin sensitive index (ISI) and morphology of pancreas were taken to evaluate pancreatic 3 cell function. At last, the vascular function test was performed. The thoracic aortic ring of SD rats was mounted on a bath system, The effect of rosiglitazone on the contraction elicited by L-phenylephrine (PE) and potassium chloride (KCl) and the relaxation induced by acetylcholine (ACh) and sodium nitroprusside (SNP) were measured. To explore the mechanism , nitric oxide synthase (NOS) inhibitor N^ω-nitro-L-arginine methyl ester (L-NAME) was used. At the same time, Blood lipid, NO, MDA, SOD, ICAM-1, VCAM-1, ET-1 levies; thoacic aortic nitric oxide synthase (NOS ) activity , MDA content, SOD activity and aortic expression of ICAM-1, VCAM-1 were measured respectively in groups.