Effect of erythropoietin on the eXpression and function of renal aquaporin－1 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(EDO)on the expression and function of aqua_porin_1( AQD _1)in the kidney of young male SD rats after release of bilateral ureter obstruction( BUO _ R). Methods Porty_eight young SD rats were randomly divided into bilateral ureteral complete obstruction(BUO)group (n﹦6),BUO_R group(n﹦12),BUO_R﹢EDO group( n﹦12)and Sham group( n﹦18). The BUO model was built through bilateral ureteral ligation. BUO group were killed after 24 h,and BUO_R group and BUO_R﹢EDO group were relieved after obstruction of 24 h. EDO(500 U∕kg)was given to BUO_R﹢EDO rats at 1 h after release of BUO,and then repeated 1 d,3 d and 5 d 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 and blood samples were collected on 3 d and 7 d(24 h,3 d,7 d for Sham group)after release of BUO. The u_rine samples were collected by using metabolic cage before death. The plasma osmotic pressure,creatinine(Cr)and u_rea nitrogen(BUN)in the plasma of young rats were detected. The expression of AQD_1 protein in all groups of kidney tissues was detected by adopting immunohistochemistry and Western blot. Results On day 3 after release of BUO,24 h water intake and urine volume of BUO_R﹢EDO group were higher than those of Sham group,but lower than those of BUO group(P〈0. 05),the urine osmotic pressure of BUO_R﹢EDO group was higher than that of BUO group,but lower than that of Sham group(P〈0. 05),while plasma osmotic pressure,Cr and BUN of BUO_R﹢EDO group were higher than those of Sham group,but lower than those of BUO group(P〈0. 05),and they were all of lower than BUO group( P 〈0. 05). On day 7 after release of BUO,there was no obvious change in Sham group,and the indexes of BUO_R group and BUO_R﹢EDO group gradually recovered,but they still did not reach the normal level(P〈0. 05). The difference between BUO_R group and BUO_R﹢EDO group was statistically significant(P〈0. 05). The immuno_histochemical results showed that the expression of AQD_1 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﹢EDO group than that of Sham group(P〈0. 05). Compared with 3 days after release of BUO,the staining intensity of BUO_R﹢EDO group and BUO_R group was enhanced,but still lower than that of the Sham group. These results were further confirmed by adopting Western blot,and BUO group was also the lowest of the four groups,and BUO_R﹢EDO group was higher than that of BUO group,but lower than that of Sham group( P〈0. 05). Conclusion EDO can promote not only the recovery of AQD_1 protein expression but also the recovery of renal function in young BUO_R rats.