Erythropoietin improves glucose metabolism and pancreatic β-cell damage in experimental diabetic rats

Previous studies have implicated erythropoietin (EPO) signaling in the regulation of glucose metabolism. Whether EPO can be used treat diabetes and the underlying mechanism remain to be elucidated. The present study aimed to investigate whether EPO affects glucose metabolism, and the underlying mechanisms, in experimental diabetic rats. The effects of EPO (300 U/kg three times a week for 4 weeks) on glucose metabolism, hematopoietic function, blood selenium content and the ultrastructure of pancreatic beta-cells were investigated in low dose (25 mg/kg body weight) streptozotocin-induced experimental diabetic rats provided with a high-fat diet. The results demonstrated that EPO significantly decreased the fasting blood glucose, the area under the curve of the oral glucose tolerance and insulin tolerance tests and L-alanine gluconeogenesis. Ultrastructural examination of the pancreatic islets revealed that EPO prevented the dysfunction of pancreatic beta-cells in experimental diabetic rats, ameliorated cytoplasmic vacuolation and fragmentation of mitochondria, and increased the number of secretory granules. EPO administration increased the activities of superoxide dismutase and glutathione peroxidase, and decreased the level of malondialdehyde. Additionally, EPO increased blood selenium in the diabetic rats and produced a hematopoietic effect. These results indicated that EPO modulated glucose metabolism and improved pancreatic beta-cells damage by increasing anti-oxidation. The detailed mechanisms underlying these effects require further investigation.