MICT/HIIT对高脂膳食大鼠心肌和比目鱼肌超微结构的影响及机制探讨

Effects of MICT/HIIT on the ultrastructure of myocardium and soleus in rats with high-fat diet and its mechanisms

目的:观察中等强度持续运动(MICT)与高强度间歇运动(HIIT)对高脂膳食大鼠心肌和比目鱼肌超微结构的影响并探讨其机制。方法:5周龄雄性SD大鼠随机分为普通膳食安静组(C)、高脂膳食安静组(F)、高脂膳食MICT组(M)和高脂膳食HIIT组(H),每组8只,高脂膳食饲料脂肪含量为45%。M和H组进行12周坡度为25°的跑台运动,M组进行70%VO_(2)max强度的持续运动,H组进行以5 min 40%~45%VO_(2)max和4 min 95%~99%VO_(2)max强度依次交替的间歇运动。干预结束后检测血清FFA、TG、HDL、LDL含量;透射电镜观察大鼠心肌和比目鱼肌超微结构;Western blot检测心肌和比目鱼肌AMPK、MCD及CPT-1的蛋白表达。结果:与C组比较,F组大鼠体重、Lee`s指数、血清LDL、TG和FFA含量均增加,HDL含量降低(P<0.05);心肌和比目鱼肌AMPK、CPT-1蛋白表达升高,MCD蛋白表达降低(P<0.05),超微结构损伤。与F组比较,M、H组大鼠体重、Lee`s指数降低、血清LDL、FFA含量降低(P<0.01);心肌AMPK、MCD、CPT-1蛋白表达增加,比目鱼肌AMPK、MCD蛋白表达增加(P<0.05),超微结构损伤减轻。与M组比较,H组大鼠血清HDL含量增加(P<0.01),心肌AMPK、MCD蛋白表达增加,超微结构损伤较轻;比目鱼肌AMPK蛋白表达降低,MCD蛋白表达增加(P<0.05),超微结构损伤较重。结论:MICT与HIIT可通过干预AMPK、MCD、CPT-1蛋白表达,对高脂膳食大鼠心肌和比目鱼肌超微结构产生不同影响。

Objective:To investigate the effects of moderate intensity continuous training(MICT)and high intensity intermittent training(HIIT)on the ultrastructure of myocardium and soleus in rats with high fat diet,and to explore the mechanisms.Methods:5-week-old male SD rats were randomly divided into normal diet quiet group(C),high-fat diet quiet group(F),high-fat MICT group(M)and high-fat HIIT group(H),with 8 rats in each group,and the fat content of the high-fat dietary feed was 45%.The M and H groups were given 12 weeks of treadmill running with an incline of 25°.The M group was given continuous exercise with 70%VO_(2)max intensity,and the H group was given intermittent exercise with 5 min 40%~45%VO_(2)max and 4 min 95%~99%VO_(2)max intensity successively.After the intervention,the contents of free fatty acid(FFA),triglyceride(TG),high density lipoprotein cholesterol(HDL)and low density lipoprotein cholesterol(LDL)in serum were detected.Transmission electron microscopy was used to observe the ultrastructure of myocardium and soleus in rats.Western blot was used to detect the protein expressions of AMPK,malonyl-CoA decarboxylase(MCD)and carnitine palmitoyl transterase 1(CPT-1)in myocardium and soleus.Results:Compared with C group,the body weight,Lee's index,the contents of LDL,TG and FFA in serum were increased,the content of HDL was decreased(P<0.05),the protein expressions of AMPK and CPT-1 in myocardium and soleus were increased,the protein expression of MCD was decreased(P<0.05),and the ultrastructure was damaged in group F.Compared with F group,the body weight and Lee's index were decreased,the contents of LDL and FFA in serum were decreased(P<0.01),the protein expressions of AMPK,MCD and CPT-1 in myocardium were increased,and the protein expressions of AMPK and MCD in soleus were increased(P<0.05),and the ultrastructural damage was attenuated in M and H groups.Compared with M group,the content of HDL in serum was increased(P<0.01),the protein expressions of AMPK and MCD in myocardium were increased,and the ultrastructural damage was mild,the protein expression of AMPK in soleus was decreased,the protein expression of MCD in soleus was increased(P<0.05),and the ultrastructural damage was severe in group H.Conclusion:MICT and HIIT have different effects on the ultrastructure of myocardium and soleus in high-fat diet rats by intervening the protein expression of AMPK,MCD and CPT-1.