Change Of MMP-2 And TIMP-2 In Kidney Of Diabetic Rat And Effect Of Cordycepic Hypha

Objective:The objective of this study is to observe the changes of MMP-2 and TIMP-2 expression in the kidneys of diabetic rats with the therapy of cordycepic hypha,to analyze the relationship between MMT-2,TIMP-2 and the fibrous degeneration correlate factor ColⅣ,to study the effects of MMP-2 and TIMP-2 on the progression of diabetic nephropathy and the reno-protective mechanism of cordycepic hypha on Streptozotocin-induced diabetic Wistar rats.Methods:After the rats model with diabetes were induced by right-nephrectomy and peritoneal injection of streptozotocin (STZ,53mg·Kg^-1),the 21 Wistar rats which with fasting blood glucose(FBG) equal to or more than 16.7mmol/L served as diabetic rats were randomly divided into following two groups:diabetes control(n=11,DM group), diabetic rats treated with cordycepic hypha(n=10,CH group).At the same time,the rats with right-nephrectomy and peritoneal injection of the equal citric acid buffer were as normal control group(n=10,NC group).Both DM group and NC group were only given 0.9%Sodium Chloride,while the CH group were treated with cordycepic hypha(4.95g·kg′·d^-1,by gavage).All rats of diabetic groups were not treated with insulin or other anti-diabetes drugs in experimental procedures.After raising rats of the three groups for 8 weeks, Plasma glucose,serum creatinine(Scr),blood urea nitrogen(BUN),and 24-hour urinary protein(Upro)were observed.And creatinine clearance(Ccr)was calculated.Then the rats in the three groups were killed.The expressions of MMP-2,TIMP-2 and Col-Ⅳin kidney were identified by immunohistochemistry and the mRNA expression levels of MMP-2,TIMP-2 and ColⅣin kidney were detected by revese transcription polymerase chain reaction(RT-PCR).The experimental data was statistically analyzed by one-way ANOVA and correlation analysis.Results:1.There were no significant differences among all groups before this experiment(p＞0.05).2.After 8 weeks,the levels of plasma glucose,Ccr and Upro in DM and CH groups were increased more significantly than NC group(p＜0.01).The levels of Ccr and Upro in CH group are lower significantly than DM group (p＜0.01).And the level of plasma glucose in DM and CH groups is not different significantly.3.The results of immunohistochemistry and RT-PCR showed that the expressions of TIMP-2 and ColⅣin DM and CH groups were much higher than NC group(p＜0.01 or p＜0.05).But the expression of MMP-2 and the relative value of MMP-2 with TIMP-2 were lower than NC group(p＜0.01 or p＜0.05).4.The results of immunohistochemistry and RT-PCR showed that the expressions of TIMP-2 and ColⅣin CH group were much lower than DM group(p＜0.01 or p＜0.05).The expression of MMP-2 and the relative value of MMP-2 with TIMP-2 were higher(p＜0.01)5.The correlation analysis showed that there was significant positive correlation of expressions between TIMP-2 and ColⅣor between TIMP-2 and 24-hour urinary protein.There were negative correlation of expressions between MMP-2 or the relative value of MMP-2 with TIMP-2 and ColⅣ.And the same between MMP-2 or the relative value of MMP-2 with TIMP-2 and 24-hour urinary protein.Conclusion:1.There were pathological changes in nephridial tissue of diabetic rat and the 24-hour urinary protein increased significantly.The expression of TIMP-2 was up-regulated in nephridial tissue of diabetic rat while that of MMP-2 and the ratio of MMP-2 with TIMP-2 were down-regulation.The expression of MMP-2 and the ratio of MMP-2 with TIMP-2 has left relationship with 24-hour urinary protein while the expression of TIMP-2 has right relationship with 24-hour urinary protein.Abnor expression of MMP-2 and TIMP-2 has close relationship with diabetic nephropathy and urinary protein.2.Expression of ColⅣhas been demonstrated to increase in nephridial tissue of diabetic rat and has left relationship with MMP-2 while has right relationship with TIMP-2.The over expression of TIMP-2 and low expression of MMP-2 promote over expression of ColⅣ,which promotes to accumulation of extracellular matrix and fibrosis in kidney3.After 8 weeks,the use of cordycepic hypha improve the function of kidney in diabetic rats,24-hour urinary protein decreased significantly. The expression of ColⅣand TIMP-2 were down-regulation,while that of MMP-2 was up-regulated.Cordycepic hypha promote the degradation of ColⅣ,restrain accumulation of extracellular matrix,delay the progression of diabetic nephropathy by correcting the abnor expression of MMP-2及TIMP-2.