EFFECT OF MODERATE EXERCISE ON RAT T-CELLS

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 (T-rest, 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.