Correlation of mTOR and VEGF Gene with Nephropathy in Diabetic Rats

［Abstract］Objective　The purpose of this study was to observe the correlation of mTOR and VEGF gene with nephropathy indicators in diabetic rats. Methods Forty-eight male Sprague-Dawley（SD）rats were divided into diabetes mellitus group （DM＝28） and control group （NDM＝20）. Diabetic models were produced by injection of streptozotocin. In the courses of 12，16，20 and 24 weeks， the histology scores（HS）and glomerular basement membrane（GBM）thickness were collected. The protein and mRNA expressions of the gene of mTOR，VEGF and VEGFR2 were observed by immunohistochemistry and real-time quantitative polymerase chain reaction （RT-Q-PCR）by SYBR Green. And the standardized cycle of threshold （SCt） was regarded as the indicators of the mRNA expression. Results HS and GBM thickness were significantly higher in DM rats than those in NDM rats，especially in DM rats of the courses of 20 and 24 weeks （P < 0.01）. IHC scores of VEGF and VEGFR2 were higher in total DM rats and were positively correlated with each other. There were positive correlations between HS with VEGF and VEGFR2 in total DM rats （P < 0.05）. SCts of VEGF and VEGFR2 were significantly higher and were positively correlated with each other in total DM rats （P < 0.01）. SCt of VEGF and GBM thickness showed positive correlation in total DM rats. SCt of VEGF was highest in the course of 12w DM rats. SCt of VEGFR2 gradually decreased following by the diabetic course， and was lowest in the course of 24w. There were no significantly differences in IHC scores and SCt of mTOR between DM and NDM rats. But the IHC scores of mTOR， VEGF and VEGFR2 were positively correlated with each other and with HS in total DM rats （P < 0.05）. Conclusion HS and GBM thickness were higher in diabetic rats， especially in the course of 24w， which could reflect the injury of nephropathy. The protein and mRNA of VEGF and VEGFR2 were high expressed in kidney of DM rats and increased with the increasing of diabetic course. The mRNA expression of VEGF was positively correlated with GBM thickness of in diabetic nephropathy （DN）. The protein expressions of mTOR， VEGF and VEGFR2 might have synergistic effects in DN of DM rats. But the results could not exclude the influences of different courses， sample size and experimental conditions