8周有氧运动对肥胖小鼠骨骼肌炎症及运动能力的影响

Effects of 8 weeks’aerobic exercise on the skeletal muscle inflammation and exercise ability of obese mice

目的探索8周有氧运动对高脂膳食诱导的小鼠肥胖的改善作用及可能的作用途径。方法C57BL/6雄性小鼠46只,随机分为正常膳食组和高脂膳食组制备肥胖小鼠模型后,再组内随机分为对照安静组(CS组)、对照运动组(CE组)、肥胖安静组(OS组)和肥胖运动组(OE组)。运动组进行8周最大运动强度60%的中等强度有氧运动。运动干预前后均对各组小鼠进行最大运动能力测试,干预期间检测小鼠能量摄入水平及体重变化。末次运动48 h后取小鼠双侧后肢背侧腓肠肌,制作骨骼肌冰冻切片,免疫荧光染色检测小鼠骨骼肌骨架蛋白Desmin分布;HE染色检测小鼠骨骼肌横截面积和炎症细胞浸润。Western Blot方法检测小鼠骨骼肌萎缩和炎症相关蛋白表达。结果与CS组相比,OS组小鼠能量摄入、体重、Atrogin-1蛋白、MuRF1蛋白和TNF-α蛋白表达均显著增加(P<0.05),运动能力、骨骼肌纤维横截面积、IL-10蛋白表达均显著下降(P<0.05),Desmin蛋白排列紊乱;有氧运动干预后,与OS组相比,OE组小鼠能量摄入无显著性差异(P>0.05),体重、Atrogin-1蛋白、MuRF1蛋白、TNF-α蛋白和IL-1β蛋白表达均显著下降(P<0.05),运动能力、骨骼肌纤维横截面积、IL-10蛋白表达均显著增加(P<0.05);另外,与CS组相比,CE组Atrogin-1蛋白、MuRF1蛋白、TNF-α蛋白和IL-1β蛋白表达均显著下降(P<0.01),IL-10蛋白表达显著增加(P<0.05)。结论高脂膳食相关肥胖诱发骨骼肌慢性炎症反应,导致骨骼肌萎缩和运动能力下降;而有氧运动有效改善肥胖诱导的骨骼肌萎缩,进而发挥提高运动能力并改善肥胖的作用,骨骼肌组织中炎症调节可能是其中的重要原因之一。

We aimed to determine the effects of 8 weeks of aerobic exercise on obesity in mice induced by high-fat diet-feeding and the mechanisms involved.Forty-six male C57 BL/6 mice were randomly allocated to a normal diet group and high-fat diet group,then to a Control Sedentary group(CS group),a Control Exercise group(CE group),an Obese Sedentary group(OS group),and an Obese Exercise group(OE group).The exercise groups underwent moderate-intensity aerobic exercise at 60%of maximum exercise intensity for 8 weeks.Before and after this exercise intervention,the maximum exercise ability of each group was determined,and the dietary energy intake and body mass of the mice were measured regularly during the intervention.The mice were euthanized and both gastrocnemius muscles were removed 48 hours after the last exercise bout.The desmin distribution in the muscles was assessed following immunofluorescence staining,and the cross-sectional area and inflammatory cell infiltration in skeletal muscle were assessed following hematoxylin and eosin staining.Western Blot was used to measure the expression of proteins related to atrophy and inflammation in skeletal muscle.The energy intake,body mass,and expression of atrogin-1,muscle ring finger(MuRF1),and tumor necrosis factor(TNF)-αprotein was significantly higher in the OS group than in the CS group(P<0.05);whereas the exercise ability,cross-sectional area of muscle fibers,and interleukin(IL)-10 protein expression were significantly lower(P<0.05).In addition,desmin protein expression was disordered.After aerobic exercise,there was no significant difference in energy intake between the OS and OE groups.However,the body mass and protein expression of atrogin-1,MuRF1,TNF-α,and IL-1βwere significantly lower in the OS group(P<0.05)and the exercise ability,crosssectional area of muscle fibers,and IL-10 protein expression were significantly higher(P<0.05).In addition,the protein expression of atrogin-1,MuRF1,TNF-α,and IL-1βin the CE group was significantly lower than in the CS group(P<0.01),whereas the IL-10 protein expression was significantly higher(P<0.05).In conclusion,high-fat diet-induced obesity is associated with chronic inflammation in skeletal muscle,which leads to skeletal muscle atrophy and a decline in exercise capacity.Conversely,aerobic exercise ameliorates this skeletal muscle atrophy,which improves exercise ability,and a reduction in local inflammation may play a key role in this effect.