The Influence Of Two Different Skeletal Muscle Working Conditions On Fat Metabolism Myokines Irisin And CTRP15

Exercise induced secretion of myokines promoting fat oxidation has been one of research hotspots in weight-loss-aimed sports activities.The aim of this study was to investigate the effect of two different muscle working conditions(centripetal and eccentric exercise)on serum Irisin and CTRP15 levels after acute exercise,in order to reveal the difference between two different muscle working conditions on regulating fat oxidation.Methods: 90 male Sprague-Dawley(SD)rats(8 weeks;weight: 200 + 20g)were selected and randomly divided to control group(n=6),flat slope group(n=30;the duration of exercise:60 minutes)and downhill group(n=30;the duration of exercise:60 minutes;the degree of slope:-5).The heart blood?gastrocnemius and soleus muscle since 0h,6h,12 h,24h and 48 h after exercise were collected from 6 rats respectively in their group(0h group,6h group,12 h group,24 h group and 48 h group).ELISA kit was used to detect the serum Irisin level,Western Blot was used to detect the expression level of FNDC5 in skeletal muscle and CTRP15 kit was used to detect the level of serum CTRP15.Results:(1)Through the same time of exercise,there was no significant difference in the level of oxygen uptake between the flat slope group and downhill group(P > 0.05).(2)The expression level of FNDC5 in 6h group increased significantly(P < 0.05)in centripetal exercise group and eccentric exercise group;Compared with the control group,there were no significant difference in 0h group,12 h group,24 h group,48 h group of centripetal exercise group;Compared with the control group,there were significant improvements in 0h group,12 h group,24 h group,48 h group of eccentric exercise.(3)Compared with control group(13.80±0.84 ng/mL),the serum irisin in eccentric exercise group was extremely elevated in 0h(15.73 ±1.31 ng/mL),12h(25.37±1.63 ng/mL),24h(15.60±1.63 ng/mL)and 48h(34.45±3.30 ng/mL)post exercise(P<0.01).Compared with control group(13.80±0.84 ng/mL),the serum irisin in centripetal exercise group was elevated in 0h(15.73 ±1.31 ng/mL),6h(18.66±1.57 ng/mL)and 24h(16.19±1.08 ng/mL)post exercise(P<0.05).(4)The comparison of the expression of CTRP15 in serum: Compared with the control group,the expression of CTRP15 in 0h group,6h group,12 h group,24 h group and 48 h group from centripetal group and 0h group,12 h group,24 h group and 48 h group from eccentric exercise were significantly higher respectively(P<0.05;P<0.01).ConclusionThe expression of FNDC5 in skeletal muscle and the concentration of serum Irisin and CTRP15 were increased in the centripetal group and eccentric group both.And compared with centripetal group,the effect of eccentric exercise was more obvious.Compared with centripetal exercise group,FNDC5 and Irisin peak twice and have longer peak time in eccentric exercise group;while in centripetal exercise group,FNDC5 and Irisin only peak once and have shorter peaking time.Acute eccentric exercise may release more myokines than centripetal exercise,thus have better effect on weight loss.