摘要
目的:探讨在糖尿病肾病(DKD)大鼠模型中,骨形态发生蛋白7(BMP7)是否通过下调Ajuba水平,降低Yes相关蛋白1(YAP1)的表达,进而减轻细胞外基质(ECM)沉积从而减轻DKD大鼠肾组织纤维化程度.方法:18只SD大鼠随机分为正常对照组(NC组)、糖尿病组(DM组)和DM+过表达BMP7腺相关病毒组(DM+rAAV-BMP7组),每组6只.采用尾静脉注射55 mg/kg链脲佐菌素(STZ)建立DM大鼠模型.NRK-52E细胞分为正常糖组、高糖(HG)组和HG+rhBMP7组.HE和天狼星红染色观察大鼠肾皮质病理形态学变化;免疫组织化学染色检测肾皮质Ajuba、YAP1的表达部位;Western blot法检测大鼠肾皮质及NRK-52E细胞中BMP7、Ajuba和YAP1、Ⅲ型胶原(Col-Ⅲ)和纤维连接蛋白(FN)的蛋白表达水平;RT-qPCR检测大鼠肾皮质Ajuba和YAP1 mRNA的表达水平.结果:生化指标检测显示DM组大鼠血糖、血肌酐、甘油三酯、总胆固醇及24 h尿蛋白水平较NC组显著升高(P<0.05),尿肌酐较NC组显著降低(P<0.05);与DM组相比,DM+rAAV-BMP7组大鼠血肌酐、24 h尿蛋白定量水平、甘油三酯和总胆固醇显著降低(P<0.05),尿肌酐显著升高(P<0.05);病理染色显示DM组肾间质出现炎症细胞浸润及胶原纤维沉积,肾小管萎缩且排列紊乱,DM+rAAV-BMP7组的病理变化较DM组显著改善;免疫组化结果显示在肾皮质中Ajuba和YAP1主要表达于细胞质和细胞核,且在DM组高表达,但DM+rAAV-BMP7组其表达则显著降低;Western blot结果显示DM组或HG组中FN、Col-Ⅲ、Ajuba和YAP1的蛋白水平上调(P<0.05),但在DM+rAAV-BMP7组中上述蛋白表达水平又显著降低(P<0.05);RT-qPCR结果显示DM组Ajuba、YAP1的mRNA水平较NC组显著上升(P<0.05),DM+rAAV-BMP7组Ajuba、YAP1的mRNA水平较DM组又显著降低(P<0.05).结论:过表达BMP7可减轻DKD大鼠的肾纤维化,其机制可能与下调Ajuba,减少YAP1的表达,从而抑制了ECM的沉积有关.
Abstract
AIM:Bone morphogenetic protein 7(BMP7)reduces the expression of Yes-related protein 1(YAP1)by down-regulating Ajuba level and decreasing extracellular matrix(ECM)deposition.This study aimed to inves-tigate the influence of these factors on modifying the degree of renal fibrosis in rats with diabetic nephropathy.METH-ODS:Eighteen Sprague-Dawley(SD)rats were randomly divided into three groups:the normal control(NC)group,the diabetes mellitus(DM)group,and the DM group treated with BMP7 overexpressing adeno-associated virus(DM+rAAV-BMP7).Each group consisted of six rats.Diabetic kidney disease(DKD)was established in the DM and DM+rAAV-BMP7 groups by injecting 55 mg/kg streptozotocin(STZ)via the tail vein.NRK-52E cells were divided into three groups:the normal glucose(NG)group,the high glucose(HG)group,and the high glucose group treated with recombinant hu-man BMP7(HG+rhBMP7)group.Pathological changes in renal tissues were observed using hematoxylin and eosin(HE)and Sirius red staining.Immunohistochemical staining was performed to examine the expression sites of Ajuba and YAP1 in the renal cortex.Western blot analysis was conducted to determine the expression levels of BMP7,Ajuba,YAP1,colla-gen type Ⅲ(Col-Ⅲ),and fibronectin(FN)in the rat renal cortex and NRK-52E cells.RT-qPCR was used to measure the mRNA levels of Ajuba and YAP1 in the rat renal cortex.RESULTS:Biochemical indices revealed significantly ele-vated levels of blood glucose,serum creatinine,triglycerides,total cholesterol,and 24-hour urinary protein in the DM group compared to the NC group(P<0.05).In the DM+rAAV-BMP7 group,the levels of serum creatinine,24-hour uri-nary protein,triglycerides,and total cholesterol were lower than those in the DM group(P<0.05).Pathological staining demonstrated that the renal interstitium of the DM group exhibited inflammatory cell infiltration,fibrous tissue,collagen fi-ber deposition,disordered renal tubule arrangement,atrophy,and vacuolar degeneration,which were ameliorated in the DM+rAAV-BMP7 group.Immunohistochemistry revealed that Ajuba and YAP1 were mainly expressed in the cytoplasm and nucleus,with high expression in the cytoplasm of the DM group,which was significantly decreased in the DM+rAAV-BMP7 group.Western blot results indicated that the protein levels of FN,Col-Ⅲ,Ajuba,and YAP1 were up-regulated in the DM and the HG groups(P<0.05),but significantly down-regulated in the DM+rAAV-BMP7 group(P<0.05).RT-qP-CR results demonstrated that the mRNA levels of Ajuba and YAP1 were higher in the DM group and significantly lower in the DM+rAAV-BMP7 group(P<0.05).CONCLUSION:The overexpression of BMP7 can ameliorate renal fibrosis in rats with DKD.This effect is likely mediated by the down-regulation of Ajuba,reduction of YAP1 expression,and subse-quent inhibition of ECM deposition.
基金项目
贵州省科技计划项目(黔科合基础-ZK[2021]重点010号)
贵州省科技计划项目(黔科合基础-ZK[2022]一般378号)
贵州省科技计划项目中央引导地方科技发展基金([2021]4029)
贵州省科技计划项目中央引导地方科技发展基金([2022]4017)
维普
万方数据