To investigate the mechanism of protective effect of erythropoietin (EPO) on renal function after releasing of bilateral ureter obstruction (BUO) in SD rats.

Thirty-two SD rats were divided into 4 groups randomly (BUO group, BUO-R group, BUO-R+ EPO group and Sham group; n=8). The BUO model was built by bilateral ureteral ligation. EPO was given to BUO-R+ EPO rats 1 h after releasing of BUO, and then repeated 12, 24, 36, 48 h thereafter and the same volume of normal saline was simultaneously given to BUO-R rats. The urine samples were collected 24 h before death and then blood samples were collected from inferior vena cava. The kidneys at both sides were harvested 72 h after releasing of BUO to examine the effect of EPO on the expression of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 by immunohistochemistry and real-time quantitative polymerase chain reaction (Real-time PCR).

The osmotic pressure in BUO-R+ EPO group was higher than that in BUO-R group, while lower than that in Sham group [(1 164±93) vs. (715±76) vs. (1 835±98) mosm/kg, P=0.000]. The hematal concentrations of urea and CREA in BUO group [(58.40±4.63) mmol/L and (277.30±11.26) μmol/L] were higher than those in other three groups, while they were higher in BUO-R+ EPO group [(12.20±2.34) mmol/L and (34.70±4.58) μmol/L] than those in Sham group [(6.40±0.75) mmol/L and (20.50±3.71) μmol/L], but lower than those in BUO-R group [(25.70±3.26) mmol/L and (52.60±7.83) μmol/L], P=0.000. Immunohistochemistry showed the expression levels of TNF-α and IL-6 were strongest in BUO group and weakest in Sham group, while those were stronger in BUO-R group than in BUO-R+ EPO group. Real-time PCR showed that the expression of TNF-α and IL-6 mRNA in BUO group was the most, while that in Sham group was the least, and that in BUO-R+ EPO group was less than in BUO-R group.

EPO could promote the recovery of renal function by inhibiting inflammatory reaction in BUO-R rats.

Erythropoietin; Ureter obstruction; Kidney; Inflammatory reaction