To observe the renal protective effects of carbamylated erythropoietin (CEPO) in rats with chronic kidney disease (CKD) complicated with acute kidney injury (AKI).

Thirty-nine healthy male SD rats (450±20 g) were randomly divided into three groups. Firstly, the model of chronic renal failure was made by 5/6 nephrectomy in rats, and was confirmed 10 days later. Afterwards, the model of complicated AKI was made by injection in the hind limb muscle with 50% glycerol at a dose of 8 ml/kg. On the 11th, 12th, and 13th day, each group was treated with intraperitoneal injection of normal saline (NS group), erythropoietin at a dose of 5 000 U/kg (EPO group), and CEPO at a dose of 5 000 U/kg (CEPO group). On the 1st, 5th, 10th, 11th, 13th, and 17th day, the body weight and blood pressure of the rats were detected. At the same time, blood from the tail vein was used to detect hematocrit, serum creatinine, and urea nitrogen, and the renal tissues were taken for pathological periodic acid-Schiff (PAS) staining. The experimental data were processed with SPSS 19.0 statistical software. P<0.05 was considered statistically significant.

Compared with the NS group, the CEPO group and the EPO group relieved the weight loss of rats (F=8.19, F=6.84, P<0.05), reduced the levels of Scr (F=5.12, F=13.72, P<0.05)and BUN (F=4.63, F=12.78, P<0.05), and reduced the renal tubular pathological damage (F=9.14, F=12.73, P<0.05). The CEPO group′s effects were more obvious than those of the EPO group (P<0.05). And CEPO relieved the increase of hematocrit, the side effect of EPO(F=8.27, P=0.019).

CEPO showed significant renal protective effects in the CKD rat model complicated with AKI. The CEPO treatment could also reduce the increased level of hematocrit.