PAX2 re-expression in renal tubular epithelial cells and correlation with renal interstitial fibrosis of rats with obstructive nephropathy

Abstract

Objective: To investigate the effect of paired box 2 (PAX2) gene re-expression in renal tubular epithelial cells on renal interstitial fibrosis in rats with obstructive nephropathy. Methods: Wistar rats were randomly divided into two groups: sham-operated group (sham group) and unilateral ureteral obstruction group (UUO group), 40 in each group. After the surgery, rats were killed at 3, 5, 7, and 14 days (n 10 each) to remove and collect kidneys. Morphological changes of the kidney were determined by histopathology. Protein and mRNA expression of PAX2 in the kidney were determined by immunohistochemistry, Western blot and real-time polymerase chain reaction (PCR). Results: The new major findings of this study include the following: (1) Hematoxylin and Eosin (HE) and Masson staining revealed obvious renal interstitial fibrosis in UUO group; (2) increased PAX2 expression was found in renal tubular epithelial cells in UUO group by immunohistochemistry, but not in sham group; (3) by Western blot, a significant increase in PAX2 protein level in UUO group was detected 3d after the surgery when compared to sham group (p < 0.05), which continued to increase with prolonged obstruction; the same pattern was also found in PAX2 mRNA expression by real-time PCR in UUO group after the surgery; (4) PAX2 protein level was positively correlated with the severity of renal tubular damage (r 0.937 and p < 0.05) and the level of renal interstitial fibrosis (r 0.987 and p < 0.05). Conclusion: In rats with obstructive nephropathy, embryonic development gene PAX2 is re-expressed in the renal tubules, which may participate in the pathogenesis of renal tubular damage and renal interstitial fibrosis. © Informa UK, Ltd.