Effect of erythropoietin on the expression and function of renal aquaporin - 2 after release of bilateral ureter obstruction in young rats / 中华实用儿科临床杂志

ABSTRACT

Objective To investigate the effect of erythropoietin(EPO)on the expression of aquaporin - 2 (AQP2)in the kidney of young SD rats after release of bilateral ureter obstruction(BUO - R). Methods Thirty - two young SD rats were equally divided into 4 groups randomly(BUO group,BUO - R group,BUO - R ﹢ EPO group and Sham group,8 rats in each group). The BUO model was built through bilateral ureteral ligation. EPO(500 U/ kg)was given to BUO - R ﹢ EPO rats at 2 h after release of BUO,and then repeated 6 h,12 h,24 h and 36 h thereafter and the same volume of 9 g/ L saline was simultaneously given to BUO - R rats. The Sham group was prepared in parallel by laparotomy and free dissection of bilateral ureters but not ligated. Both side kidneys were harvested 48 h(72 h for Sham group)after release of BUO to examine the effect of EPO on the expression of AQP2 in inner medulla by immunohisto-chemistry,Real - time PCR and Western blot. The urine samples were collected by using metabolic cage before death. Results The osmotic pressure of BUO - R ﹢ EPO group was higher than that of BUO - R group,but lower than that of Sham group(P ﹤ 0. 05). Immunohistochemistry showed that the collecting duct wall thinned and lumen enlarged. After the pictures were analysized by using Image - Pro Plus software,it showed that the expression of AQP2 in collecting duct in BUO group was significantly down - regulated compared with that in Sham group,whereas,it was slightly weaker in BUO - R group and BUO - R ﹢ EPO group than Sham group(P ﹤ 0. 05). These results were further confirmed by a-dopting Western blot,and the relative quantity of AQP2 in BUO group was also the lowest of the four groups(P ﹤0. 05). Real - time PCR showed that the level of AQP2 mRNA in Sham group was(24. 30 ± 1. 03)folds of BUO group,(10. 60 ± 1. 05)folds of BUO - R group and(5. 70 ± 1. 01)folds of BUO - R ﹢ EPO group,respectively. Conclusion EPO could promote not only the recovery of AQP2 mRNA and protein expression but also the recovery of AQP2 function in young BUO - R rats.