马兜铃酸损伤大鼠肾小球足细胞的研究

目的 探讨马兜铃酸是否能损害肾小球足细胞.方法 用关木通浸膏水溶液间断灌胃制作马兜铃酸肾损害大鼠模型,分别于第1、4周末检测早期马兜铃酸肾损害大鼠24 h尿蛋白量,并以十二烷基磺酸钠-聚丙烯酰胺凝胶电泳观察尿蛋白成分.随后处死大鼠取肾组织,用激光显微切割捕获技术分离肾小球；用实时荧光定量PCR检测肾小球中nephnn、podocin、CD2AP、podocalyxin、podoplanin的mRNA表达；电镜下测量肾小球足突的平均宽度.结果 模型大鼠4周末尿蛋白量较对照组显着增多(P＜0.01),其中白蛋白含量明显增加.电镜结果显示肾小球足突平均宽度较对照组显著增宽(P＜0.01).肾小球中nephrin、podocin、CD2AP、podocalyxin、podoplanin的mRNA表达均较对照组显著减少,分别下调34％、62％、56％、50％(P＜0.01)及27％(P＜0.05).结论 马兜铃酸能损伤肾小球足细胞,导致足细胞相关蛋白mRNA表达下调,足突节段增宽,并出现白蛋白尿.

Study of glomerular podocyte injury induced by aristolochic acid

Objective To explore whether the glomerular podocytes can be damaged by aristolochic acid. Methods Thirty-two male SD rats were equally divided into the following 2 groups: model group in which the rats received the extract of Aristolochia manshuriensis Kom (AmK) by gavage; control group only received tap water by gavage. 24 h urinary protein excretion was measured at the end of the 1st and 4th week, and SDS-PAGE gel electrophoresis was performed to detect the protein in urine. At the end of the 4th week, all the rats were sacrificed and the glomeruli were isolated by laser capture microdissection technique. The mRNA expression of nephrin, podocin, CDA2P, podocalyxin and podoplanin in isolated glomeruli was determined by RT-PCR, and the average width of glomerular foot process was measured by electron microscopy and image analysis. Results At the end of the 4th week, 24 h urinary protein excretion in the model group was significantly higher than that in the control group (P<0.01) and the urinary albumin content in model group was also obviously increased. The average width of glomerular foot process in the model group was significantly larger than that in control group (P<0.01). The mRNA expressions of nephrin, podocin, CDA2P, podocalyxin and podoplanin in glomeruli were significantly down-regulated in the model group compared with the control group, which decreased by 34%, 62%, 56%, 50%(P<0.01) and 27% (P<0.05), respectively. Conclusions Aristolochic acid can damage the glomerular podocytes, resulting in the down-regulation of nephrin, podocin, CD2AP, podoplanin and podocalyxin mRNA expression, the segmental widening of foot process, and increased urinary protein excretion.