【摘要】 目的:探讨急性(1次)和长期(8周)高强度间歇训练(HIT)对SD大鼠不同类型骨骼肌纤维代谢与分布的影响。方法:30只雄性SD大鼠随机分为安静对照(r-C)组、急性HIT(a-HIT)组和长期HIT(c-HIT)组,每组n=10只。a-HIT组进行1次急性HIT,c-HIT组进行8周HIT,r-C组保持安静状态。实验后分离胫骨前肌(快肌,II型肌纤维为主)和比目鱼肌(慢肌,I型肌纤维为主),比色法测定琥珀酸脱氢酶(SDH)和乳酸脱氢酶(LDH)活性,ATP酶染色法鉴定肌纤维类型(I、II),Western Blot法测定腺苷酸活化蛋白激酶(AMPK)α亚基(AMPKα)、磷酸化AMPKα(p-AMPKα)、p38促分裂原活化蛋白激酶(p38 MAPK)、p-p38 MAPK、钙调神经磷酸酶(Ca N)、过氧化物酶体增殖物激活受体γ辅激活因子1α(PGC-1α)、激活T细胞核因子(NFAT)c1亚基(NFATc1)蛋白相对表达量以及肌球蛋白重链(MHC)亚型(I、IIa、IId/x和IIb)百分构成比。结果:与r-C组比较,a-HIT组比目鱼肌和胫骨前肌糖原含量均下降(P<0.05),p-AMPKα/AMPKα、p-p38 MAPK/p38 MAPK、Ca N、PGC-1α和NFATc1蛋白表达量升高(P<0.05);c-HIT组力竭时间延长(P<0.05),胫骨前肌LDH活性升高,比目鱼肌和胫骨前肌糖原含量、SDH活性以及PGC-1α和NFATc1蛋白表达量升高(P<0.05),比目鱼肌IIa型和IIb型肌纤维比例减少(P<0.05),I型肌纤维比例增加(P<0.05),胫骨前肌IIb和IId/x型肌纤维减少(P<0.05),IIa和I型肌纤维增加(P<0.05)。结论:一次急性HIT可同时募集快肌和慢肌纤维并激活多种信号转导通路;而长期HIT则提高快肌中I型和IIa型肌纤维以及慢肌中I型肌纤维比例,上调快肌和慢肌糖原含量和有氧代谢酶活性以及快肌无氧代谢酶活性,最终改善运动能力。更多还原

【Abstract】 Objective: To investigate the effects of acute( a bout of) and long-term( 8 weeks) high intensity interval training( HIT) on metabolism and distribution of different fiber-type skeletal muscle in SD rats. Methods: Thirty male SD rats randomly divided into resting control( r-C,n = 10) group,acute high intensity interval training( a-HIT,n = 10) group and chronic high intensity interval training( c-HIT,n = 10) group. Rats of a-HIT group performed a bout of acute HIT and those of c-HIT group conducted 8 weeks HIT,while those of r-C group maintained resting state. After the experiment,anterior tibial muscle( fast muscle,mainly type II muscle fibre) and soleus muscle( slow muscle,mainly type II muscle fibre)were segregated,succinate dehydrogenase( SDH) and lactate dehydrogenase( LDH) activity were measured by colorimetric method,muscle fiber type by ATPase staining,protein relative expression level of adenosine monophosphate activated protein kinase( AMPK) α subunit( AMPKα),phosphorylation of AMPK( p-AMPKα),p38 mitogen-activated protein kinase( p38 MAPK),p-p38 MAPK,Calcinerin( Ca N),peroxisome proliferator activated receptor γ coactivator-1α( PGC-1α)and nuclear factor of activated T cells( NFTA) c1 subunit( NFATc1),as well as percentage constituent ratio of myosin heavy chain( MHC) isoforms( I,IIa,IId/x and IIb) by Western Blot. Results: Compared with r-C group,glycogen content reduced( P < 0. 05),protein expression level of p-AMPKα/AMPKα,p-p38 MAPK/p38 MAPK,Ca N,PGC-1α and NFATc1 raised( P < 0. 05) in anterior tibial muscle and soleus muscle of a-HIT group; exhausted duration extended( P < 0.05),LDH activity increased( P < 0. 05) in anterior tibial muscle,while glycogen content,SDH activity,protein expression level of PGC-1α and NFATc1 elevated( P < 0. 05) in anterior tibial muscle and soleus muscle,proportion of type IIa and IIb muscle fibers reduced( P < 0. 05) but type I muscle fiber raised( P < 0. 05) in soleus muscle,while proportion of type IIb and IId/x muscle fibers reduced( P < 0. 05) but type IIa and I muscle fiber raised( P < 0. 05) in anterior tibial muscle. Conclusion: A bout of acute HIT could simultaneously recruit fast and slow muscle fibers and activate multiple signal pathways,while long-term HIT increased proportion of type I muscle fibers in fast muscle and type I and IIa muscle fibers in slow muscle,upregulated glycogen content and enzymic activity of aerobic metabolism in fast and slow muscle,enzymic activity of anaerobic metabolism only in slow muscle,thus improving exercise capacity.更多还原