Abstract des Autors

Background: To evaluate the in vitro effects of corticosterone, equivalent to blood levels measured after a single submaximal treadmill exercise, on apoptosis and necrosis of mouse thymic and peripheral lymphocytes. Methods: Experimental design: analysis of variance with independent factors of time (0, 90, 210 minutes of incubation) and concentration of corticosterone (0, 150, 250, 450, 850 ng/ml). Measures: percentage of apoptotic, necrotic, and viable thymocytes and splenocytes determined by flow cytometry using Annexin V-FITC antibody and propidium iodide. Results: There was a significantly higher % of apoptotic thymocytes at 210 min at the higher corticosterone concentrations but not in % of apoptotic splenocytes at the same time point. For both lymphoid populations, corticosterone incubation was associated with a higher % of necrotic cells at 210 minutes but not at 0 or 90 minutes. For thymocytes, the interaction (time x concentration) was significant, with greater % necrosis observed at the lower (150 and 250 ng/ml) concentrations of corticosterone. Conclusions: The data suggest that in vitro exposure to corticosterone, at physiological concentrations (</=450 ng/ml) observed after a moderate exercise stress, induces apoptosis in thymocytes and necrosis in both thymocytes and splenocytes. The implications for exercise-mediated glucocorticoid regulation of immune function remain to be investigated. Verf.-Referat