胰高血糖素样肽-2改善后肢悬吊诱导的小鼠骨骼肌萎缩

Glucagon-like peptide-2 improves hindlimb suspension-induced skeletal muscle atrophy in mice

中文关键词: 肌少症  骨骼肌  废用性肌萎缩  胰高血糖素样肽-2  蛋白激酶B

英文关键词: sarcopenia  skeletal muscle  disuse muscular atrophy  glucagon-like peptide-2  protein kinase B

中文摘要:

      目的 研究胰高血糖素样肽-2(GLP-2)对后肢悬吊诱导小鼠骨骼肌萎缩的作用.方法 18只8周龄C57BL/6雄性小鼠随机分为对照组(Control组)、后肢悬吊组(HLS组)和干预组(HLS+GLP-2组),每组6只.HLS+GLP-2组小鼠每日皮下注射GLP-2(300 μg·kg-1·d-1),HLS组和Control组小鼠每日皮下注射同体积1％DMSO对照溶剂,干预4周后取材.称量肌肉重量,测量小鼠肌力;HE染色和肌纤维横截面面积评估肌纤维萎缩情况;qRT-PCR和Western blot检测肌肉代谢标志物及肌肉代谢关键调控信号的磷酸化水平.结果 干预4周后,各组小鼠体质量均增加,但3组间体质量差异无统计学意义(P＞0.05).与Control组相比,HLS组小鼠股四头肌(QD)、胫前肌(TA)、腓肠肌(GA)和比目鱼肌(SOL)重量均减少(P＜0.05);与HLS组相比,HLS+GLP-2组小鼠GA和SOL重量增加(P＜0.05).与Control组相比,HLS组小鼠肌力下降(P＜0.01);与HLS组相比,HLS+GLP-2组小鼠肌力改善(P＜0.05).与Control组相比,HLS组小鼠GA肌纤维形态萎缩、肌纤维横截面面积减少(P＜0.001).HLS+GLP2组小鼠较HLS组肌肉萎缩改善,肌纤维横截面面积增加(P＜0.05).Western blot结果显示,与Control组相比,HLS组小鼠GA的肌肉特异性环指蛋白1(MuRF-1)和肌肉萎缩F盒蛋白(Atrogin-1)表达增加(P＜0.05),生肌调节因子(MyoD)和肌细胞生成素(MyoG)蛋白表达降低(P＜0.05).与HLS组相比,HLS+GLP-2组小鼠GA的MuRF-1和Atrogin-1蛋白表达降低(P＜0.05),MyoD(P＜0.01)和MyoG(P＜0.05)蛋白表达升高.与Control组相比,HLS组小鼠GA中蛋白激酶B(AKT)磷酸化水平较对照组下降(P＜0.05);与HLS组相比,HLS+GLP-2组小鼠GA的AKT磷酸化水平上升(P＜0.05).结论 GLP-2能有效改善后肢悬吊诱导的小鼠骨骼肌萎缩,且该调节可能与AKT磷酸化相关.

英文摘要:

      Objective To explore the effects of glucagon-like peptide-2(GLP-2)on hindlimb suspension-induced skel-etal muscle atrophy in mice.Methods A total of 18 8-week-old male C57BL/6 mice were randomly divided into three groups:control group,hindlimb suspension group(HLS group)and intervention group(HLS+GLP-2 group),with 6 mice in each group.Mice in the HLS+GLP2 group received daily subcutaneous injections of GLP-2(300 μg·kg-1·d-1),while mice in the control group and HLS group were administered an equivalent volume of 1％DMSO solvent.The samples of skele-tal muscles were harvested for analysis after 4 weeks of intervention.Muscle weight and grip strength were measured.HE stai-ning and muscle fiber cross-sectional area(CSA)were used to assess atrophy.qRT-PCR and Western blot analyzed expression of muscle metabolism markers and phosphorylation levels of key regulatory signaling pathways.Results After 4 weeks,body weight increased in all groups without statistical significance(P＞0.05).Compared with the control group,the HLS group showed significant reduction in weights of quadriceps(QD),tibialis anterior(TA),gastrocnemius(GA)and soleus(SOL)(P＜0.05);compared with the HLS group,the weights of GA and SOL in the HLS+GLP-2 group increased(P＜0.05).Compared with the control group,the muscle strength in the HLS group decreased(P＜0.01);compared with the HLS group,the muscle strength in the HLS+GLP-2 group improved(P＜0.05).Compared with the control group,the morphology of GA fibers in the HLS group atrophied and the cross-sectional area of muscle fibers decreased(P＜0.001);the muscle atrophy in the HLS+GLP2 group was improved compared with the HLS group,and the cross-sectional area of muscle fibers increased(P＜0.05).The Western blot results showed that compared with the control group,the expressions of muscle-specific ring fin-ger protein 1(MuRF-1)and muscle atrophy Fbox protein(atrogin-1)in GA in the HLS group increased(P＜0.05),and the protein expressions of myogenic regulatory factor(MyoD)and myosonietin(MyoG)decreased(P＜0.05).Compared with the HLS group,the protein expressions of MuRF-1 and Atrogin-1 in GA in the HLS+GLP-2 group decreased(P＜0.05),while the protein expressions of MyoD(P＜0.01)and MyoG(P＜0.05)increased.Compared with the control group,the phosphorylation level of protein kinase B(AKT)in GA in the HLS group decreased(P＜0.05);compared with the HLS group,the phosphorylation level of AKT in GA in the HLS+GLP-2 group increased(P＜0.05).Conclusion GLP-2 im-proves HLS-induced skeletal muscle atrophy in mice,and this regulation may be related to AKT phosphorylation.