Effect of moderate exercise on rat T-cells

Summary The aim of this study was a detailed examination of the effects of moderate exercise on T-cells in adult male Wistar rats. The T-cell populations were compared in sedentary rats (C, n = 5) and in rats trained for 4 weeks on a treadmill (30–60 min·day^–1, 6 days·week^–1, 20–30 m·min^–1) and sacrificed at rest (Trest, n=5). In the T-rest rats, there were higher percentages of CD4+CD8–, CD4– CD8 + and CD4 – CD8 –thymocytes (P<0.05, P<0.05 and P<0.01 respectively) and of CD4–CD8 + splenocytes (P< 0.01), and a lower percentage of CD4–CD8+ cells in the lymph nodes (P<0.01). Compared with T-rest or C rats, trained rats (n = 5) or untrained rats (n = 5) sacrificed immediately after a running session (60 min, 30 m·min^–1) had a higher percentage of mononucleated cells CD4 + CD8 -in the blood (P<0.05 and P<0.01). Lastly, compared with C rats, rats (n=5) sacrificed immediately after their 5th day of training (30–60 min·day^–1) presented a higher total splenocyte population (P<0.05) and greater in vitro production of T-cell growth factor (interleukin 2 + interleucin 4) by splenocytes in response to a mitogen (P<0.01). These results would indicate that moderate endurance training modifies the cellular composition of lymphoid organs, without impairing the in vitro functions of T-cells.