To elucidate the relationship between the reexpression of the embryonic developmental gene PAX2 in renal interstitial fibrosis rats and renal tubular epithelial-mesenchymal transition cell phenotype (EMT) specific markers E-cadherin and α-SMA, and to explore the role of PAX2 of action in renal interstitial fibrosis.

A total of 80 male Wistar rats were randomly divided into the sham group (n=40) and UUO model group (n=40). Renal tissues were sacrificed at 3, 5, 7 and 14 d (10 rats in each group) after operation. The pathological and morphological changes of the kidney were observed under light microscope. The relationship between PAX2 and E-cadherin / α-SMA was detected by immunohistochemical double staining. The expression of PAX2, E-cadherin and α-SMA mRNA in renal tissue was detected by real-time fluorescent quantitative PCR.

①HE and Masson staining showed obvious fibrosis in the UUO group; ② Double staining results showed that PAX2 protein was not expressed in renal tubular epithelial cells, E-cadherin protein was abundantly expressed in renal tubular epithelial cells, and α-SMA protein was expressed only in the muscular layer of small arteries. PAX2 There was no co-expression between E-cadherin and α-SMA; in the UUO group, the expression of PAX2 and α-SMA became more pronounced with the increase of the obstruction time, the expression of E-cadherin gradually decreased, and the area of co-expression of PAX2 and α-SMA protein increased; ③PCR results: PAX2 mRNA was slightly expressed in the renal cortex of the sham group, E-cadherin mRNA was heavily expressed, and α-SMA mRNA was slightly expressed; compared with the sham group, PAX2 mRNA was expressed in the 3d UUO group, while the E-cadherin mRNA expression was reduced, and α -SMA mRNA expression increased. With the extension of obstruction time, PAX2 mRNA and α-SMA mRNA expression gradually increased, and E-cadherin mRNA expression decreased significantly. There were statistically significant differences in the relative expression of mRNA at each time point between the UUO group, the sham group and the UUO group (all P values <0.05). ④Correlation analysis showed that PAX2 mRNA level was positively correlated with α-SMA mRNA level ( r=0.993, P<0.05), and negatively correlated with E-cadherin mRNA level (r=-0.983, P<0.05).

The expression of embryonic development gene PAX2 in renal tubular epithelial cells of renal interstitial fibrosis rats has a certain relationship with the expression of E-cadherin / α-SMA protein and mRNA in phenotype-specific markers of EMT cells.The PAX2 re-expression is involved in the EMT process of renal interstitial fibrosis.

Renal interstitial fibrosis; Paired box 2 gene; E-cadherin; α-SMA