evaluation of immune response after moderate and overtraining exercise in wistar rat

objective(s): the effect of prolonged overtraining on cytokine kinetics was compared with moderate exercise in the present study.   materials and methods: male wistar rats were randomly divided into control sedentary (c), moderate trained (mt), (v=20 m/min, 30 min/day for 6 days a week, 8 weeks), overtrained (ot) (v=25 m/min, 60min/day for 6 days a week, 11 weeks) and recovered overtrained (or) (ot plus 2 weeks recovery) groups, (n=6 for each group). immediately, 24 hr and 2 weeks (in or) after last bout of exercise blood samples were obtained. the plasma concentrations of tnfα, il-6, il-10, il-4 and ifn were measured by elisa method. results: immediately after last bout of exercise the following findings were observed; il-6, il-10 and tnfαconcentrations increased in ot and or groups compared with control (p<0.05–p<0.001). serum level of il-4 decreased (p<0.01) but ifn increased (p<0.05) in mt group vs. control. in addition, circulatory levels of tnfα il-6, il-10 and il-4 were higher but the ifn concentrations were lower in ot and or groups than mt group (p<0.05-p<0.01). the ifn-γil4 ratio was significantly increased in mt (p<0.01) while it decreased in ot group. there were not statistical differences in tnfα il-6, and ifn levels between different time intervals after exercise in mt, ot and or groups. conclusion: these data confirm a positive effect of moderate exercise on immune function and a decrease in susceptibility to viral infection by inducing th1 cytokine profile shift. however, prolonged and overtraining exercise causes numerous changes in immunity that possibly reflects physiological stress and immune suppression.