Mechanism of endurance training-induced erythrocyte deformability in rats involves erythropoiesis

Higher erythrocyte deformability may reduce the risk of circulatory diseases by enhancing oxygen delivery and reducing the load on the cardiovascular system. The effect of endurance training on erythrocyte deformability is not clear. This study explored the impact of endurance training on erythrocyte deformation and shape and investigated the underlying mechanisms of hemorheological alterations. Forty male Wistar rats were randomly divided into two groups: sedentary (S; n = 21) and exercised (E; n = 19). Hematological indices and erythrocyte shape were measured at the end of the 11th week. The gene expression of erythropoietin (Epo) and the Epo receptor (EpoR) was quantified using reverse transcription-PCR (RT-PCR), and Epo protein expression was analyzed using Western blotting. Endurance training significantly decreased the abnormality ratio of erythrocyte shape (P < 0.01). The deformability indicator (DI) of red blood cells was lower in the E group than in the S group (P < 0.01). Eleven weeks of endurance training increased Epo mRNA and protein expression in the kidney (P < 0.01), EpoR mRNA expression in the bone marrow (P < 0.05), and relative circulating Epo (P < 0.01) compared to the sedentary group. The decrease in the erythrocyte morphological index and the maximum of deformability indicator were associated with an increase in relative circulating Epo. In conclusion, 11 weeks of endurance training increased erythrocyte deformability. Epo and EpoR may contribute to the decreased morphological index and deformability indicator in erythrocytes during endurance training in rats.