AMPKα2在高强度间歇运动激活小鼠骨骼肌细胞自噬过程中的作用

The Role of AMPKα2 in High-intensity Interval Training-activated Autophagy in the Skeletal Muscle of C57BL/6 Mice

目的:探讨6周高强度间歇运动(high-intensity interval training,HIIT)对小鼠体成分和骨骼肌自噬活性的影响,以及AMPKα2在运动影响小鼠体成分和运动调节小鼠骨骼肌自噬过程中的作用。方法:4周龄C57BL/6雄性小鼠36只,其中包括AMPKα2+/+,AMPKα2+/-,AMPKα2-/-三种基因型小鼠各12只,各基因型小鼠随机分为安静对照组(Control组)和高强度间歇运动组(HIIT组),每组6只。各运动组小鼠给予6周HIIT干预,HIIT包括2分钟85%VO2max强度与1分钟50%VO2max强度的跑台运动交替进行12个循环,1次/天,5次/周。6周运动干预结束后对各组小鼠分别进行体重、身体质量指数(BMI)、总体液量、体脂含量等身体指标测定;采用Western blot法检测小鼠骨骼肌组织AMPKα2,p AMPK-Thr172,LC3Ⅱ/Ⅰ,Beclin1及p62蛋白表达水平。结果:(1)与Control组同基因型小鼠相比,运动开始前各组小鼠体重无显著差异,运动结束后,HIIT组小鼠体重较安静对照组小鼠显著降低(P<0.05);HIIT组中,AMPKα2+/+和AMPKα2+/-小鼠的BMI水平显著下降(P<0.01或P<0.05),而AMPKα2-/-小鼠与Control组相比BMI水平无明显变化(P>0.05);三种基因型小鼠总体液量均无显著性差异(P>0.05);HIIT组小鼠中,AMPKα2+/+和AMPKα2+/-小鼠体脂含量下降显著(P<0.05),AMPKα2-/-小鼠体脂含量下降但无显著性(P>0.05);(2)HIIT干预后AMPK+/+和AMPK+/-小鼠骨骼肌组织较安静对照组p AMPK-Thr172,LC3Ⅱ/Ⅰ,Beclin1表达上调而p62表达下降(P<0.05),而在AMPK-/-小鼠上述蛋白表达变化无显著性。结论:HIIT通过提高骨骼肌组织AMPKα2磷酸化水平有效降低小鼠体重、体脂含量和BMI等健康指标,并显著增加骨骼肌细胞自噬活性。

Objective To investigate the effect of 6-week high-intensity interval training（HIIT） onthe body composition and the autophagy activation in skeletal muscle of C57 BL/6 mice,and explore theunderlying role of adenosine 5＇-monophosphate（AMP）-activated protein kinase（AMPK）α2 in this pro-cess. Methods Thirty-six 4-week old male mice with the genotype AMPKα2＋/＋（n=12）,AMPKα2＋/-（n=12） and AMPKα2-/-（n=12）,were randomly divided into a control（n=6） and an HIIT group（n=6） respec-tively. The mice from the HIIT group exercised on a motor-driven rodent treadmill for 5 days a week,lasting 6 weeks. The procedure of HIIT included the intensity of 85% VO2 max（20 m/min） for 2 min/day and 50% VO2 max（8 m/min） for 1 min/day with 12 cycles alternately. The body weight,body massindex（BMI）,total body water and fat mass were measured and analyzed after the 6-week exercise. Theprotein expression of AMPKα2,p AMPK-Thr172,LC3 II/I,Beclin1 and p62 in the skeletal muscle tissue were detected using Western blotting. Results Before exercise,there was no significant difference be-tween the mice of the same genotype in the body weight. However,a significant decrease was observedin the body weight of all the HIIT mice,and BMI of the AMPKα2＋/＋and AMPKα2＋/-mice undergoingHIIT. There were no significant differences in the total body water between the control and HIITgroups of the same genotype after the intervention. There was significant decrease in the body fat massin the HIIT group of AMPKα2＋/＋and AMPKα2＋/-mice after the intervention,while the decrease was notsignificant in the HIIT AMPKα2-/-mice. The protein expression of p AMPK-Thr172,LC3 II/I and Beclin1 increased significantly,and that of p62 decreased significantly in the skeletal muscle of the AMPK＋/＋and AMPK＋/-mice after HIIT intervention,but not the AMPK-/-mice. Conclusion HIIT can improvehealth indicators（i.e. body weight,BMI and fat mass） and enhance autophagy activation in the skeletalmuscle through increasing the phosphorylation of AMPKα2.