Simvastain's renoprotection effects and its influence on MCP-1mRNA expression of renal tissue in STZ-induced diabetic rats

Objective To investigate the renoprotective effects of simvastain and its influence on the expression of MCP-1mRNA in kidney tissue and urinary MCP-1 excretion of diabetic rats.Methods 24 Wistar Rats were assigned to normal control group(group C,n=8),STZ-induced diabetes mellitus group(group D,n=8) and simvastain(20 mg·kg-1·d-1) treatment group(group S,n=8).The peripheral blood glucose was measured at the 2nd,4th and 8th week and HbA1c was assessed at the 8 th week.At the 8 th week,the urinary excretion rates of albumin (ALB),retinal-binding protein(RBP) and monocyte chemoattractant protein-1(MCP-1) were tested and relative kidney index was calculated.The renal tissues of diabetic rats were obtained for RT-PCR to examine the gene expression of MCP-1 in renal tissue.Results ①The blood glucose levels at the 2nd,4th and 8th week and HbA1c at the 8th week in groups D and S were significant higher than those in group C at the same period(P0.01);②At the 8 th week,not only the urinary excretion rates of ALB,RBP and MCP-1,but also the relative kidney index were markedly increased in groups D and S compared with group C(P0.01).However,the parameters above in group S were much lower than those in group D(P0.01).In addition,the urinary excretion of MCP-1 was positively correlated to the urinary ALB excretion,the urinary RBP excretion and relative kidney index;③Pathological changes observed by electron microscope of group S were much lighter than those of group D,but a little heavier than those of group C;④ In comparison with group C,the expression of MCP-1mRNA was significantly up-regulated in group D and group S;the expression of MCP-1 mRNA in group S was reduced markedly compared with that in group D(P0.05).Conclusion Simvastain has renoprotective effects through down-regulating the over-expression of MCP-1 mRNA in renal tissue and reducing urinary excretion of MCP-1 in STZ-induced diabetic rats.