To investigate the protective effect of erythropoietin (EPO) on renal function after releasing of bilateral ureters obstruction (BUO-R) in young SD rats.

From October 2015 to June 2016, forty young SD rats were bought and equally divided into 4 groups randomly (BUO group, BUO-R group, BUO-R+ EPO group and Sham group; n=10) according to random number table. The BUO model was built by bilateral ureteral ligation. EPO (500 U/kg) was given to BUO-R+ EPO rats immediately after releasing of BUO, and then repeated 2d, 4d and 6d thereafter and the same volume of normal 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. The urine samples were collected by metabolic cage 24h before death and then blood samples (1 ml) were collected from inferior vena cava.

The urine osmolarity of Sham group was the highest [(1 794±103)mOsm/kg], BUO-R+ EPO group was (1 257±82)mOsm/kg, and BUO-R group was the lowest [(756±69)mOsm/kg]; Whereas the urine output of Sham group was the lowest [(26±5)μl/(min·kg)], BUO-R+ EPO group was (48±7)μl/(min·kg), and BUO-R group was the highest [(71±9)μl/(min·kg)]; P<0.05. The concentrations of urinary K⁺ , Na⁺ and creatinine in BUO-R+ EPO group were [(133.8±5.8)mmol/L, (134.7±4.9)mmol/L and (3 549±482)μmol/L]lower than those in Sham group [(154.7±6.5)mmol/L, (149.3±7.8)mmol/L and (4 537±624)μmol/L], but higher than those in BUO-R group [(112.4±7.2)mmol/L, (106.5±6.3)mmol/L and (2 612±536)μmol/L], P<0.05. The concentrations of hematal K⁺ , urea and creatinine in three experimental groups were all higher than those in Sham group; of which the hematal K⁺ , urea and creatinine in BUO group were the highest[(12.1±0.7)mmol/L, (47.6±6.0)mmol/L and (252.8±18.7)μmol/L], the BUO-R group took the second place [(8.5±0.5)mmol/L, (7.8±0.4)mmol/L and (55.2±4.8)μmol/L], and the BUO-R+ EPO group came third [(7.4±0.5)mmol/L, (6.4±0.3)mmol/L and (36.4±3.6)μmol/L], while the Sham group were the lowest [(6.8±0.3)mmol/L, (5.6±0.24)mmol/L and (23.6±2.7)μmol/L]; P<0.05. While the hematal Na⁺ concentration in BUO group was the lowest [(126.4±5.9)mmol/L], and BUO-R group was the highest [(147.3±4.9)mmol/L], the Sham group was the second lowest [(136.7±4.3)mmol/L], and the BUO-R+ EPO group was the second highest [(141.5±5.7)mmol/L], P<0.05.

EPO could promote the recovery of renal function and normalize the altered renal water and salt handling function in young BUO-R rats.

Erythropoietin; Ureter obstruction; Renal function