Pleiotropic and renoprotective effects of erythropoietin beta on experimental diabetic nephropathy model

Background: This study aimed at investigating the possible protective effect of erythropoietin beta on experimental diabetic nephropathy (DN) model in rats. Methods: Sprague Dawley rats (n = 32) were allocated into 4 equal groups of 8 each, the control (Group C), diabetes (Group D), erythropoietin beta (Group E), and erythropoietin beta treated DN (Group E + D) groups. Streptozocin (65 mg/kg) was used to induce diabetes in 10-week old rats. Erythropoietin beta was given intraperitoneally at a dose of 500 IU/kg/3 days of a week for 12 weeks. Renal function parameters, intrarenal levels and activities of oxidative stress biomarkers, serum inflammatory parameters and kidney histology were determined. Results: Group E + D had lower mean albumin-to-creatinine ratio (p < 0.001) as well as higher creatinine clearance (p = 0.035) than the diabetic rats (Group D). Intrarenal malondialdehyde levels were significantly lower (p = 0.004); glutathione (GSH) levels (p = 0.003), GSH peroxidase (p = 0.004) and superoxide dismutase (p < 0.005) activities of renal tissue were significantly higher in Group E + D than in Group D. The mean serum levels of interleukin-4 (p < 0.005), interleukin 1 beta (p = 0.012), interferon gamma (p = 0.018) and tumor necrosis factor alpha (p < 0.005) were significantly lower; serum levels of monocyte chemoattractant protein 1 (p = 0.018) was significantly higher in Group E + D when compared to Group D. The mean scores of tubulointerstitial inflammation (p = 0.004), tubular injury (p = 0.013) and interstitial fibrosis (p = 0.003) were also lower in Group E + D when compared to Group D. Conclusion: Our data seem to suggest a potential role of erythropoietin beta for reducing the progression of DN in an experimental rat model. This protective effect is, in part, attributable to the suppression of the inflammatory response and oxidative damage.