糖尿病基础研究

　　[摘要] 目的 探讨AT1受体自身抗体(AT1-AA)对DN大鼠肾脏内质网应激(ERS)相关因子GRP78和CHOP表达的影响。 方法 制备DN大鼠模型，ELISA法检测血清AT1-AA，根据ELISA结果随机选择AT1-AA阳性和阴性DN大鼠纳入DN组(n=12)，同时设立正常对照组(NC，n=6)。电镜观察肾脏超微结构变化;TUNEL法检测肾脏细胞凋亡;RT-PCR测定大鼠肾组织GRP78和CHOP mRNA水平;Western blot分析肾组织中GRP78和CHOP蛋白的表达量。 结果 DN组肾脏细胞凋亡率较NC组升高，其中,AT1-AA阳性大鼠凋亡率高于AT1-AA阴性大鼠[(20.05±1.71)vs (13.24±4.93)](P<0.01)。与NC组相比，DN组肾组织GRP78，CHOP蛋白和mRNA水平均上调;进一步比较发现，AT1-AA阳性DN大鼠GRP78，CHOP蛋白及mRNA水平升高较AT1-AA阴性DN大鼠更明显。 结论 AT1-AA可能通过诱导DN大鼠肾脏ERS反应，并经ERS相关的CHOP凋亡信号通路而促进肾脏细胞凋亡，加重肾脏损害。

　　[关键词] AT1受体;自身抗体;GRP78;CHOP;糖尿病肾病

　　[Abstract] Objective To investigate the influence ofAT1 receptor autoantibodies (AT1-AA) on the expression of endoplasmic reticulum stress-related factors Glucose Regulated Protein 78( GRP78) and CCAAT/enhancer-binding protein homologous protein (CHOP) in diabetic nephropathy (DN) rats. Methods After establishing DN model rats, serum AT1-AA was measured by enzyme-linked immunosorbent assay (ELISA). AT1-AA positive or negative DN rats were randomly selected as DN group (n=12). 6 normal control rats were set as NC group. Pathological changes of the kidney were observed by electron microscope.TUNEL stainingwas used to evaluate cell apoptosis. Western blot for the protein expression of ERS-related factors GRP78 and CHOP were performed. Additionally, RT-PCR was used to measure the mRNA levels of GRP78 and CHOP. Results Compared with NC group, DN group showed the renal cell apoptosis rate was significantly higher. The apoptosis rate was much higher in AT1-AA positive DN rats than in AT1-AA negative DN rats [(20.05±1.71) vs (13.24±4.93), P<0.05)]. Compared with NC group, the levels of GRP78, CHOP proteins and mRNA in DN group were significant higher. These proteins and mRNA levels significantly increased in AT1-AA positive DN rats when compared with AT1-AA negative DN rats. Conclusion AT1-AA may induce ERS reaction in the kidney of DN rats, which then promotes renal cell apoptosis likely via the modulation of ERS-related CHOP signaling pathway.

　　[Key words] AT1 receptor; Autoantibody; Glucose Regulated Protein 78( GRP78); CCAAT/enhancer-binding protein homologous protein (CHOP); Diabetic nephropathy