Effects of intensive training on Th1/Th2 balance and its mechanism

Objective To investigate the molecule mechanism of exercise induced Th1/Th2 imbalance through observing and analyzing the change of Th1/Th2 balance and the relationship with IL-12. Methods Sprague-Dawley rats aged 16 weeks were randomly divided into 2 groups: 1) Control(group A), 2) Training(group B). Each group was further randomly divided into two sub-groups according to the time of sampling: 1) 24 h post training and 2) 7 d post training. Rats in the group B performed incremental load swimming training for 4 weeks. The concentrations of IFN-γ, IL-4, IL-12 in plasma of heart blood were measured. Results The levels of plasma IFN-γ(P0.01), IFN-γ/IL-4(P0.05) and IL-12(P0.01) in the group B were all significantly lower than those in the group A. The concentrations of these three cytokins in plasma collected at 7 d post-training were lower than that collected at24 h post-training, but all of them were not significantly different with each other. The concentration of IL-12 in plasma was correlated positively with that of IFN-γ in plasma in the group A and the group B(P0.01). Conclusion(1) Th1-type immune response is effectively suppressed and Th1/Th2 imbalance is induced in response to four weeks of incremental load training. The suppression may be associated with the decreased production of IL-12.