An Investigation On The Relationship Between Exercise-induced Th1/Th2Imbalance And Change Of JAK2/STAT4Pathway In Rats

Objective:Thl/Th2imbalance in rats was induced by means of incremental load training, while two groups of rats under training were stimulated through acupuncture treatments in ZuSanLi (St-36). During the process, the changes of JAK2/STAT4pathway and upstream cytokines were observed and analysed so as to investigate the molecule mechanism of strenuous training induced Thl/Th2imbalance.Methods:Sixteen-week-old male Sprague-Dawley rats of clean grade were randomly divided into four groups:1) Control (group C),2) Training and normal recovery (group T),3)3) Training and30minutes immobilization during recovery (group TB),4) Training and30minutes immobilization plus acupuncture at ST-36during recovery (group TBA). Each group was further randomly divided into two sub-groups according to the time of sampling:1)24h post training and2)7d post training. Group T, TB and TBA performed incremental load swimming training5sessions per week for four weeks. In Group TB and TBA,30minutes immobilization was applied30minutes post each training session in week3and4. Group TBA also received acupuncture at acupoint St-36in both legs. The concentrations of IFN-γ, IL-4, IL-12in plasma of heart blood were measured using ELISA, while the expression of pJAK2, pSTAT4, JAK2and STAT4in lymphocytes were measured using Western Blotting technique. Univariate analysis of variance was performed to compare the mean values and Pearson correlation analysis was performed to measure the correlation between the concentration of IFN-γ and that of IL-12.Results:(1) The level of plasma IFN-γ (P<0.01), IFN-γ/IL-4(P<0.05) and IL-12(P<0.01) in group T were all significantly lower than that in group C. The concentrations of these three cytokins in plasma collected at7d post-training were lower than that collected at24h post-training, but all of them were no significantly different to each other. The concentration of plasma IL-4in group T was not significantly different compared with that in group C. The concentration of plasma IL-12correlated positively with that of plasma IFN-γ in group C and group T (P<0.01).(2) The expression of protein of pJAK2(P<0.05) and pSTAT4 (P<0.01) within T lymphocytes in group T were significantly lower than that in group C. The two cytokins within T lymphocytes collected at7d post-training were lower than that collected at24h post-training. The protein concentration of JAK2and STAT4within T lymphocytes in group T showed no significant difference compared with that in group C.(3) All these cytokins in group TBA had no significant differences compared with that in group T and group TB.Conclusions:(1) Th1-type immune response was effectively suppressed and Th1/Th2imbalance was induced in response to four weeks of incremental load training. Th1/Th2imbalance induced by training could continue for some time and went worse.(2) The protein concentrations of pJAK2and pSTAT4, as the key factors of JAK2/STAT4signaling pathway, were suppressed and less IFN-γ were produced through the decreased production of IL-12after four weeks of incremental load training.(3) Acupuncture at ST-36post training did not show significant effect on Th1/Th2imbalance and JAK2/STAT4signal pathway.