4周运动训练小鼠骨骼肌脂滴包被蛋白、比较基因识别58及肌内三酰甘油的表达

Expression of perilipin,comparative gene identification-58 and triglyceride in mouse skeletal muscle after 4 weeks of endurance training

背景:骨骼肌中也存在比较基因识别58和脂滴包被蛋白的表达,国内外的研究大都集中在训练骨骼肌激素敏感性脂肪酶调节脂肪分解的作用上,对运动时骨骼肌肌内三酰甘油、脂滴包被蛋白家族与比较基因识别58变化的研究较少。目的:观察4周运动训练C57BL/6J小鼠骨骼肌脂滴包被蛋白家族和比较基因识别58的变化,探讨其与肌内三酰甘油变化的关系。方法:80只6周龄雄性健康SPF级C57BL/6J小鼠,按运动训练前,运动1,2,3,4周5个时相,随机分为对照组和耐力训练组各5组。耐力训练组第1周为适应性训练;正式训练4周,每周6d,训练时间在早上8:00-12:00,以16 m/min,5%度坡度进行40 min跑台运动;安静组自由饮食。检测小鼠体质量和血液指标;小鼠腓肠肌和比目鱼肌肌内三酰甘油含量、脂滴包被蛋白家族和比较基因识别58基因及蛋白的表达。结果与结论:①耐力训练对小鼠体质量、血糖和游离脂肪酸的变化没有影响,降低血总三酰甘油、血总胆固醇和胰岛素水平(P <0.05),增加高密度脂蛋白胆固醇水平(P <0.05);②比目鱼肌中的肌内三酰甘油高于腓肠肌;耐力训练时,骨骼肌肌内三酰甘油先降后升(P <0.05);③耐力运动过程中,骨骼肌(比目鱼肌和腓肠肌)脂滴包被蛋白家族(除PLIN2)、比较基因识别58基因和蛋白显著增加(P <0.05);④耐力训练早期,脂滴包被蛋白家族(除PLIN2)、比较基因识别58基因和蛋白的表达变化参与了对肌内三酰甘油水解的调节;随后其效果减弱,揭示肌内三酰甘油合成途径的影响大于分解途径。

BACKGROUND:Comparative gene identification-58 and perilipins(2-5)are expressed in skeletal muscle.There are many studies addressing hormone sensitive lipase regulating steatolysis in skeletal muscle,but changes of triglyceride,perilipin family proteins and comparative gene identification-58 in skeletal muscle during exercise are little reported.OBJECTIVE:To investigate the effects of 4-week endurance training on the expression of perilipin family proteins and comparative gene identification-58 in C57BL/6J mice,and to explore their correlation with triglyceride level.METHODS:Eighty 6-week-old male healthy SPF C57BL/6J mice were randomly divided into control group and endurance training group according to the time-points pre-exercise,1,2,3 and 4 weeks post-exercise.The first week of endurance exercise was adaptive training,and the formal training lasted for 4 weeks,6 days weekly,the training time in the morning 8:00-12:00,with 16 m/minute,5%degree slope for 40 minutes of treadmill exercise.Mice in the control group were allowed free access to food.The body mass and blood indexes were tested.The triglyceride level,expression of perilipin family proteins and comparative gene identification-58 in mouse gastrocnemius and soleus were detected.RESULTS AND CONCLUSION:Endurance training showed no effect on mouse body mass,blood glucose and free fatty acids,and significantly reduced blood total triglyceride,total cholesterol and insulin levels(P<0.05),and increased the level of high density lipoprotein cholesterol(P<0.05).The intramuscular triglyceride of the soleus muscle was higher than that of the gastrocnemius muscle.During the period of endurance training,intramuscular triglycerides firstly reduced and then rose(P<0.05).In the working muscles(soleus and gastrocnemius)perilipin family proteins(except perlipin 2),comparative gene identification-58 mRNA and protein were significantly increased(P<0.05).In summary,in the early stage of endurance training,changes in perilipin family proteins(except PLIN2),comparative gene identification-58 mRNA and protein expression participate in the regulation of hydrolysis,and their participation is weakened thereafter,indicating intramuscular triglyceride synthesis on fat is stronger than its hydrolysis.