Recombinant human erythropoietin mitigates reductions in renal klotho expression.

BACKGROUND: Erythropoietin (EPO) and Klotho expression have both been detected in the kidney. Since a recent study suggested that both EPO and Klotho mitigate kidney damage, we explored the relation between EPO and Klotho in a doxorubicin hydrochloride (DXR)-induced rat nephropathy model treated with recombinant human erythropoietin (rhEPO). METHODS: Male Sprague-Dawley rats were subjected to DXR-induced nephropathy. The rhEPO group was intracutaneously injected with rhEPO twice weekly at 4-16 weeks after the DXR injection. The rats were sacrificed at 16 weeks after the DXR administration. Expression of renal Klotho, HSP70, alpha-smooth-muscle actin and E-cadherin were assessed using real-time PCR or western blotting. The hematocrit, plasma creatinine and phosphate levels were also determined. Immunohistochemical studies and Masson-trichrome staining were performed. RESULTS: The renal Klotho mRNA and Klotho protein expressions were significantly reduced in the DXR nephropathy group. Treatment with rhEPO improved the serum creatinine, phosphate level and histological changes observed in the DXR nephropathy group. The reduction in Klotho expression induced by DXR nephropathy was mitigated by rhEPO administration. CONCLUSION: rhEPO is involved in the pathophysiology of DXR nephropathy. rhEPO mitigated elevated plasma phosphate concentrations in an experimental model of chronic kidney disease via the expression of Klotho.