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

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(Pa0.01).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(Pa0.01),and both peaked at the 28th day.3.Meanwhile the expression of PAX2 mRNA in model group increased(Pa0.01),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(Pa0.01).4.Both the expressions of protein of PAX2 and α-SMA were significantly positively correlated with the renal interstitial fibrosis index(r=0.886,0.918Pa0.05),and there was positive correlation between the expression of protein of α-SMA and PAX2(r=0.880P0.05).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.