PAX2在单侧输尿管梗阻大鼠肾小管间质纤维化中的作用

Effect of PAX2 on Renal Tubulointerstitial Fibrosis in Rats with Unilateral Ureteral Obstruction

目的通过检测PAX2和α-平滑肌肌动蛋白(α-SMA)在单侧输尿管梗阻(UUO)大鼠肾脏组织中的表达,探讨PAX2在肾小管间质纤维化中的作用机制。方法雄性6周龄Wistar大鼠48只随机分为模型组和对照组,每组各24只。模型组在无菌条件下于左侧背部肋下切口行左侧输尿管结扎术,对照组只探及肾包膜,不结扎输尿管。于造模第7、14、21、28天各处死大鼠6只,取其左侧肾脏组织行HE和Masson染色检测肾脏病理改变,计算肾小管间质纤维化指数。采用实时荧光定量PCR检测其肾组织PAX2mRNA表达,免疫组织化学方法检测其肾脏组织PAX2及α-SMA蛋白表达。结果1.病理结果显示:对照组各时间点肾小管及间质均无明显变化。随着梗阻时间的延长,模型组大鼠肾小管间质纤维化指数逐渐增高(Pa<0.01)。2.对照组大鼠肾组织仅有少量PAX2mRNA表达,而模型组第7天表达增高,随着梗阻时间的延长,PAX2mRNA表达逐渐增高,于第28天达最高,与对照组各时间点比较,PAX2mRNA表达有显著性差异(Pa<0.01)。3.模型组大鼠肾小管上皮细胞PAX2的蛋白表达及肾间质α-SMA的蛋白表达于第7天均增高,随梗阻时间的延长,PAX2蛋白表达及α-SMA表达逐渐增高,于第28天最高,与对照组各个时间点比较有显著性差异(Pa<0.01)。4.模型组大鼠肾小管上皮细胞PAX2蛋白表达与肾间质α-SMA表达呈显著正相关(r=0.880P<0.05),PAX2蛋白及α-SMA的表达均与肾小管间质纤维化指数均呈显著正相关(r=0.886,0.918Pa<0.05)。结论PAX2可能参与UUO大鼠模型肾小管上皮细胞-肌成纤维细胞转分化,使间质中肌成纤维细胞的数量增多,引起细胞外基质积聚增加,导致了肾小管间质纤维化的发生发展。

ObjectiveTo evaluate the expression of PAX2 and α-smooth muscle actin（α-SMA） in renal tissues of rats with unila-teral ureteral obstruction（UUO）,and to investigate the effect of PAX2 on renal tubulointerstitial fibrosis.MethodsForty-eight Wistar male rats（6-week-old）were randomly assigned into the models and the control group.In the model group,the left ureters of rats were dissociated and obstructed through dorsal surface inferocostally.The control group was dissociated left ureter only,and not to be obstructed.Six rats of both 2 groups were killed at the 7th,14th,21th,28th day after surgery,respectively.Histological changes of renal tubular interstitium was observed by HE and Masson staining to observe the renal interstial fibrosis index.The expressions of PAX2 mRNA of the left renal cortex were assessed by real-time quantitative PCR,immunohistochemistry was performed to assess the expressions of PAX2 and α-SMA of the left renal tissues.Results1.The fibrosis index in the model group were significantly increased as compared with that in the control group at different time points（Pa〈0.01）.2.Immunohistochemistry staining indicated that the expression of PAX2 and α-SMA in model group increased significantly compared with that in the control group at different time points（Pa〈0.01）,and both peaked at the 28th day.3.Meanwhile the expression of PAX2 mRNA in model group increased（Pa〈0.01）,and peaked at the 28th day.The expression level of PAX2 mRNA in model group was obviously higher than that in control group at different time points（Pa〈0.01）.4.Both the expressions of protein of PAX2 and α-SMA were significantly positively correlated with the renal interstitial fibrosis index（r=0.886,0.918Pa〈0.05）,and there was positive correlation between the expression of protein of α-SMA and PAX,（r=0.880P〈0.05）.ConclusionsPAX2 may play a role in tubular epithelial-myofibroblast transdifferentiation in UUO rats,since the number of the myofibroblast cell increased in renal interstitium,which resulted in large accumulation of extracellular matrix,and contribute to renal tubulointerstitial fibrosis.