Effects of physical exercise on the concentration of 5-HT in different cerebral tissues and peripheral Th1/Th2 balance of rats under chronic stress

OBJECTIVE To probe into the effects and its possible neuroimmune mechanisms of physical exercise on the concentration of 5-HT in different cerebral tissues and the Thl/Th2 cytokine balance (IFN-γ and IL-4) of rats under chronic stress. METHODS 40 male SD rats were randomly divided into 4 groups: control group, model group, exercise model group and exercise group. The rat model of chronic stress was made by restraint for 6 hours per day, altogether 21 days. Exercise mode was unloading swimming for 60 min/t/d for 8 weeks. The concentration of 5-HT in hippocampus and occipital cortex was measured by high performance liquid chromatography. ELISA was employed to measure the levels of interferon-γ (IFN-γ) and interleukin-4 (IL-4) in serum, and the ratio of IFN-γ/IL-4. RESULTS Compared with control group, the concentration of 5-HT in hippocampus and occipital cortex, the level of IFN-γ and the ratio of IFN-γ/IL-4 significantly decreased in model group (P﹤0.01). Compared with model group, exercise model group got higher level of 5-HT, IFN-γ and the ratio of IFN-γ/IL-4 (P ﹤ 0.05). The concentration of 5-HT increased more significantly in exercise group than that in control group (P ﹤ 0.05). CONCLUSION By enhancing central 5-HT system function and maintaining immune homeostasis, exercise can lower neuroimmune injury caused by chronic stress.