2型糖尿病肾病大鼠肾动脉上BMP2/Smad1/Runx2/Osterix信号通路的激活

目的探讨2型糖尿病肾病(DN)大鼠模型肾动脉钙化及BMP2/Smad1/Runx2/Osterix信号通路的激活情况。方法 40只大鼠随机分为对照组和2型糖尿病肾病组(DN组,STZ加高脂高糖饮食诱导的2型DN大鼠模型),采用钙离子试剂盒检测8、12、16周时肾动脉钙含量,Von Kossa染色观察肾动脉上钙盐沉积。免疫组化检测肾动脉的BMP2、Smad1、Runx2及Osterix蛋白表达,RT-PCR法检测肾动脉BMP2及Runx2 mRNA水平。结果DN组大鼠各时间点血糖、尿素氮、胱抑素C及24 h尿白蛋白水平均较对照组明显增高(P0.05),自实验12周后,DN组大鼠的血肌酐值较对照组显著增高(P0.05)。DN组大鼠肾动脉组织钙含量较同时间点对照组明显增加(P0.05),Von Kossa染色见对照组大鼠各时间点均无明显钙盐沉积,而DN组大鼠肾动脉自第8周时即有黑色颗粒沉积,随着时间的延长沉积的黑色钙盐逐渐增多并聚集成团。与对照组相比,DN组大鼠肾动脉组织中BMP2及其下游因子的表达明显升高,同时BMP2、Runx2 mRNA水平亦增加。相关性分析表明,肾动脉钙含量与BMP2、Runx2 mRNA均呈显著正相关(r=0.641,r=0.683,均P0.01)。结论 2型糖尿病肾病模型大鼠肾动脉早期即可出现血管钙化,且BMP2/Smad1/Runx2/Osterix信号通路激活在其中起重要调节作用。

Activation of BMP2/Smad1/Runx2/Osterix Signal Pathway in Renal Artery of Type 2 Diabetic Nephropathy Rats

Aim To explore the calcification of renal artery and the activation of BMP2/Smad1/Runx2/Osterix signal pathway in type 2 diabetic nephropathy rats. Methods Forty rats were randomly divided into control group and diabetic nephropathy group (DN group). Type 2 diabetic nephropathy model was established by high sugar and fat diet and streptozotocin (STZ) injection. The calcium content were detected by calcium assay kit in 8,2 and 16 weeks. Calcium depositing in the renal artery was observed by Von Kossa staining. The protein expression of BMP2, Smad1, Runx2 and Osterix were detected with immunohistochemistry. Real-time polymerase chain reaction (RT-PCR) were applied to detect the gene expression levels of BMP2 and Runx2 in the renal artery. Results Contents of blood glucose, blood urea nitrogen(BUN), cystatin C (CysC) and 24 h urinary albumin (24 h UA) of DN group at all time point were much higher than those of control group (P<0.05). Serum creatinine (SCr) of DN group was higher than that of control group since 12th week (P<0.05). The calcium content in DN group were significantly higher than those in control group at each time point (P<0.05). Black granules were found deposited in the renal artery of DN rats in 8 weeks and the black calcium salt was gradually increased with the time passing. No calcium salt was found in control group. Compared with the control group, the protein expression of BMP2/Smad1/Runx2/Osterix signal pathway and the expression of BMP2, Runx2 mRNA in DN group rats were significantly higher. Correlation analysis demonstrated that calcium content was positively correlated with BMP2, Runx2 mRNA(r=0.641, r=0.683,all P<0.01) . Conclusion The renal artery calcification may appear in the early stages of type 2 diabetic nephropathy rats model and the activation of BMP2/Smad1/Runx2/Osterix signal pathway may be an important regulating factor in the renal artery calcification.