Protective effect of carbamoylated erythropoietin against renal ischemia-reperfusion injury in rats

Objective To investigate the protective effect of carbamoyl-erythropoietin (CEPO) against ischemia-reperfusion (IR) injury in rat kidneys and in human renal tubular epithelial cells (HK-2). Methods In a SD rat model of renal IR injury, EPO or CEPO was intraperitoneally injected at the dose of 5 000 U/kg at 0, 24, and 48 h after renal IR. Serum levels of urea nitrogen (BUN) and creatinine (Scr), hematocrit (Hct), and the levels of superoxide dismutase (SOD), malondialdehyde (MDA), and tumor necrosis factor-α (TNF-α) in the kidney homogenate were detected; serum levels of interleukin-6 (IL-6) and IL-10 were detected and PAS staining was used for assessment of the renal pathologies. HK-2 cells were exposed to IR injury and treated with EPO or CEPO, and the mRNA expressions of IL-6, IL-10, and TNF-α were detected using Real-time PCR; the protein expressions of IL-6, IL-10, and cleaved Caspase-3 were analyzed with Western blotting. Results In the rat model of renal IR injury, Scr, BUN and IL-6 levels were reduced and serum IL-10 level was increased significantly after treatment with EPO or CEPO, which also significantly lowered the levels of MDA and TNF-α and increased SOD levels in the kidney homogenate (P < 0.05). PAS staining showed a significant improvement of renal pathological damages after the treatments, and the effect was more obvious with CEPO. CEPO treatment resulted in a milder increase in Hct as compared with EPO (P < 0.05). In HK-2 cells with IR injury, both EPO and CEPO treatment reduced the mRNA expressions of TNF-α and IL-6, increased the mRNA and protein expressions of IL-10, and reduced the protein expressions of IL-10 and cleaved Caspase-3, and these effects were significantly more obvious with CEPO than with EPO treatment (P < 0.05). Conclusion CEPO can alleviate renal IR injury in rats by reducing inflammation and apoptosis, and can more effectively suppress the elevation of Hct than EPO in the rat models.