跑台运动对肥胖小鼠骨骼肌CHI3L1表达的影响及其机制

Effects of Treadmill Running on CHI3L1 Expression in Skeletal Muscles of High-Fat Diet Mice and its Underlying Mechanism

目的:观察跑台运动对高脂饮食诱导的肥胖小鼠骨骼肌几丁质酶-3样蛋白-1(CHI3L1)表达的影响及机制探讨。方法:5周龄健康雄性C57BL/6小鼠随机分成对照组和高脂喂养组,分别进行普通饲料和高脂饲料喂养,8周后筛选肥胖小鼠16只,随机分为高脂安静组和高脂运动组。跑台训练持续8周,每周5次,每次60分钟,跑速25米/分钟。测定小鼠体重,免疫组化法观察比目鱼肌和腓肠肌CHI3L1的蛋白表达水平,real-time PCR方法分别测定比目鱼肌和腓肠肌CHI3L1、TNF-α和IL-6的m RNA表达。结果:与对照组相比,高脂饮食喂养小鼠体重显著增加(P<0.01);比目鱼肌和腓肠肌CHI3L1的m RNA表达均显著上调(P<0.01和P<0.001),腓肠肌中CHI3L1的蛋白表达显著增加,比目鱼肌中CHI3L1的蛋白水平没有显著改变;腓肠肌TNF-α和IL-6 m RNA表达均显著上调(P<0.001和P<0.01),比目鱼肌中TNF-α和IL-6 m RNA表达有上调趋势,但无显著差异。与单纯高脂饮食组小鼠相比,8周跑台运动小鼠体重显著降低(P<0.01);比目鱼肌和腓肠肌CHI3L1 m RNA表达显著下降(P<0.001),CHI3L1蛋白表达均显著减少;腓肠肌TNF-α和IL-6 m RNA表达均显著下调(P<0.001和P<0.01),但比目鱼肌TNF-α和IL-6 m RNA表达无显著变化。结论:跑台运动能显著减少肥胖小鼠比目鱼肌和腓肠肌CHI3L1的表达,显著下调腓肠肌促炎因子TNF-α和IL-6的表达,提示运动通过减轻肥胖时骨骼肌炎症间接地调节骨骼肌CHI3L1表达。

Objective To observe the effect of treadmill running on the expression of skeletal mus-cle chitinsae 3-like-1（CHI3 L1）,pro-inflammatory factor tumor necrosis factor-α（TNF-α） and interleu-kin-6（IL-6） in the soleus and gastrocnemius muscle of high-fat diet induced obesity mice and ex-plore its mechanism. Methods Five-week-old male C57 BL/6 mice were randomly divided into a con-trol group of 8 and a high-fat diet（HFD） group of 16. The control group was given normal food,whilethe HFD group were provided with high-fat diet for eight weeks and further divided into a sedentaryHFD group and a treadmill running HFD group,each of 8. The exercise mice underwent 60 min tread-mill running at 25 m/min each day,5 days/week for 8 weeks. The body weight was measured. The ex-pression of chitinase 3-like-1（CHI3 L1） in the soleus and gastrocnemius was determined using the im-munohistochemical staining,while the m RNA expression of CHI3 L1,pro-inflammatory factors includingthe tumor necrosis factor-α（TNF-α） and interleukin-6（IL-6） in the soleus and gastrocnemius musclewere detected using the real-time polymerase chain reaction. Results Compared with the control group,a significant increase was observed in the body weight,the expression of CHI3 L1 m RNA in the soleus and gastrocnemius（P〈0.01 and P〈0.001）,the expression of CHI3 L1 protein,TNF-α and IL-6 m RNAin the gastrocnemius（P〈0.001 and P〈0.01） of the HFD group,while there was an increase in the ex-pression of TNF-α and IL-6 m RNA but without significance and no significant differences in the pro-tein expression of CHI3 L1 in the gastrocnemius of the HFD group. Compared with the sedentary HFDgroup,a significant decrease was found in the body weight,the expression of CHI3 L1 protein andCHI3 L1 m RNA in the soleus and gastrocnemius,the level of TNF-α and IL-6 in the gastrocnemiusbut not in the soleus of the treadmill running HFD group. Conclusion The exercise training can sig-nificantly decrease the expression of CHI3 L1 in the soleus and gastrocnemius,as well as the level ofpro-inflammatory factor TNF-α and IL-6 m RNA in obese mice,which indicates that exercise trainingcan regulate the expression of CHI3 L1 through alleviating inflammation in the gastrocnemius.