Correlation between the ratio of intima to tunica media thickness and the expression of bone matrix proteins in small renal artery of diabetic nephropathy rats / 中华肾脏病杂志

ABSTRACT

Objective To observe the expression of bone matrix proteins and the change of intima-tunica media thickness ratio in diabetic rat small renal artery and to explore their correlation and effects on diabetic nephropathy. Methods Seventy healthy SD rats were randomly divided into diabetic group(DN,n=40)and normal control group(N,n=30).DN rat model was induced by streptozotocin(STZ)intraperitoneal injection and the N group rats were given the same dose of citrate buffer.Thirty-five rats were successfully induced in DN group.The rats were sacrificed at week 4,12 and 24,respectively.The protein and mRNA expression of core-bind factor alpha 1(Cbfcd).bone morphogenetic protein 2(BMP-2)and matrix Gla protein(MGP)in smallrenal artery were detected by immunohistochemistry,in-situ hybridization and real-time PCR at each time point. Results Cbfctl and BMP-2 were expressed obviously in small renal artery of DN group by immunohistochemistry stain and in-situ hybridization from 4 to 24 weeks compared with N group at each time point,reaching the peak at week 24.Real-time PCR showed that the MGP mRNA was evidently increased at week 4,slightly decreased at week 12,lowest at week 24in DN group.The BMP-2 mRNA began to increase from week 4 onward,being peak at week 24in DN group.The ratio of intima to tunica media thickness had no significant difference in DN group compared with N group at week 4,but at week 12 and 24 there were significant difference between them.There was a positive correlation between Cbfα1 and BMP-2 expression,but they were negatively correlated with the expression of MGP.The ratio of intima to tunica media thickness was significantly-correlated with the expression of Cbfα1 and BMP-2. Conclusions The ratio of intima to tunica media thickness is positively correlated with Cbfα1 and BMP-2 in small renal artery of early DN.Cbfα1,BMP-2 and MGP may be involved in the progression of vascular lesions in DN.