Effects Of BCAA On Rat’s Skeletal Muscle Inflammation Process And Macrophage State After A Single Eccentric Exercise

Objective:The effects of BCAA supplementation on the inflammatory response of rats after sports injury after one-time centrifugal exercise were observed,the effects of serum inflammatory cytokines IL-6 and IL-10 were observed and the infiltration degree of M1 and M2 macrophages were observed,providing a theoretical basis for the effect of BCAA on the inflammatory process after sports muscle injury.Method:96 male SD rats aged 8 weeks were randomly assigned to placebo(N=48)or BCAA(N=48)in this study,Armstrong’s centrifugal motion model was used to establish the EIMD rats.The changes of serum inflammatory cytokines(IL-6 and IL10)in the quiet group and at different time points(immediately,1 day,3 days,5 days and 7 days)after exercise were observed.The infiltration of M1/M2 macrophages(CD68 and CD163 proteins)detected by immunohistochemical method were observed.Results:(1)Different degrees of muscle fiber necrosis,tissue edema and inflammatory cell infiltration were observed in the exercise group by HE staining,which indicated that the exercise model caused sports injury.(2)In the control group,Compared with group pre-exercise,the serum IL-6 concentration was significantly higher on the first,third and fifth days after exercise(P<0.05);IL-10 concentration was significantly higher on day 3,5 and 7(P<0.01);The expression of M1 macrophages in skeletal muscle was significantly higher on immediately,1,3,5 and 7 days after exercise(P<0.01).The expression of M2 macrophages was significantly higher at 1,3,5 and 7 days after exercise(P<0.01).(3)In the BCAA group,compared with group pre-exercise,the serum IL-6 concentration was significantly higher on day 1 and day 3 after exercise(P<0.05);IL-10 concentration was significantly higher than that before exercise at 1,3,5 and 7 days after exercise(P<0.05);The expression of M1 macrophages in skeletal muscle was significantly higher at immediately,1,3,5 and 7 days after exercise(P<0.01).The expression of M2 macrophages was significantly higher at 1,3,5 and 7 days after exercise(P<0.01).(4)Compared with the control group,serum IL-6 in BCAA group was significantly increased on the 1st day after exercise(P<0.05),and significantly decreased on the 3rd and 5th days after exercise(P<0.05);IL-10 was significantly increased on the 3rd day after exercise(P<0.01),and significantly decreased on the 5th day after exercise(P<0.05);The expression of M1 macrophages in skeletal muscle was significantly increased immediately and on day 1 after exercise(P<0.01),and significantly decreased on day 3,5 and 7 after exercise(P<0.05).The expression of M2-type macrophages was significantly increased on the 1st and 3rd days after exercise(P<0.01),but there was no significant difference on the 5th and 7th days(P>0.05).Conclusion:1)120min high-intensity centrifugal exercise caused skeletal muscle injury in rats;2)BCAA supplementation can accelerate the process of inflammatory response,from pro-inflammatory to anti-inflammatory;3)The supplementation of BCAA increased the infiltration of macrophages to the injured muscle and accelerated the polarization of M1 macrophages to M2 type,which accelerates the polarization of Ml-type macrophages to M2-type macrophages,which can regulate the immune function of the body and contribute to the repair after injury.