跑台运动对成年脊髓损伤小鼠运动功能及运动皮质mTOR信号通路的影响  

Effects of treadmill exercise on the motor function and mTOR signal pathway in motor cortex of adult mice after spinal cord injury

作　　者：詹祖雄 谭波涛[1] 王昀杭 赵秦 刘媛 李森 龙在云 杨策 殷樱[1] Zhan Zu-Xiong;Tan Bo-Tao;Wang Yun-Hang;Zhao Qin;Liu Yuan;Li Sen;Long Zai-Yun;Yang Ce;Yin Ying(Department of Rehabilitation Medicine,the Second Affiliated Hospital of Chongqing Medical University,Chongqing 400010,China;State Key Laboratory of Trauma,Burns and Combined Injury,Department of Research Institute of Surgery,Daping Hospital,Army Medical University,Chongqing 400042,China)

机构地区：[1]重庆医科大学附属第二医院康复医学科,重庆400010 [2]陆军军医大学特色医学中心(大坪医院)特殊环境战伤防治研究室/创伤、烧伤与复合伤国家重点实验室,重庆400042

出　　处：《解放军医学杂志》2022年第7期685-693,共9页Medical Journal of Chinese People's Liberation Army

基　　金：国家自然科学基金(82002377);重庆市自然科学基金(cstc2019jcyj-msxmX0195,cstc2020jcyj-msxmX0161);陆军军医大学创伤、烧伤与复合伤国家重点实验室开放课题(SKL2021011)。

摘　　要：目的观察跑台运动对成年脊髓损伤小鼠运动功能及运动皮质哺乳动物雷帕霉素靶蛋白(mTOR)信号通路的影响。方法30只C57BL/6J小鼠随机分为假手术组、模型组与跑台运动组,每组10只。所有小鼠进行跑台运动预训练3 d后,模型组和跑台运动组小鼠予以C_(5)背侧皮质脊髓束、左侧皮质脊髓束及红核脊髓束钳夹损伤,假手术组仅剔除椎板。跑台运动组伤后7 d开始跑台运动,5 d/周,共4周。采用BMS评分、水平楼梯实验和圆筒攀爬实验评估小鼠运动功能恢复情况;Western blotting检测小鼠运动皮质脑源性神经营养因子(BDNF)、胰岛素样生长因子1(IGF-1)的表达,以及酪氨酸激酶受体B(TrkB)、胰岛素样生长因子1受体(IGF-1R)、蛋白激酶B(Akt)、核糖体S6蛋白(S6)的磷酸化水平;免疫荧光染色检测运动皮质神经元S6的磷酸化水平,评估皮质mTOR信号通路激活情况。结果伤后模型组与跑台运动组小鼠BMS评分出现短暂下降(P<0.0001),并于伤后7 d恢复至基线水平。伤后3 d、1周、3周、5周,模型组和跑台运动组左前、左后肢错误率明显高于假手术组(P<0.001);伤后3周和5周,跑台运动组左前、左后肢错误率明显低于模型组(P<0.001)。伤后3 d和1周,模型组和跑台运动组左前肢使用率明显低于假手术组(P<0.0001);伤后3周和5周,模型组左前肢使用率明显低于跑台运动组和假手术组(P<0.05),而跑台运动组与假手术组比较差异无统计学意义(P>0.05)。Western blotting和免疫荧光染色检测结果显示,与假手术组比较,模型组和跑台运动组小鼠运动皮质BDNF、IGF-1蛋白相对表达水平以及TkrB、IGF-1R、Akt、S6磷酸化水平明显降低,神经元细胞内p-S6染色荧光强度明显降低(P<0.01);与模型组比较,跑台运动组小鼠运动皮质BDNF、IGF-1蛋白相对表达水平以及TkrB、IGF-1R、Akt、S6磷酸化水平明显升高,神经元细胞内p-S6染色荧光强度明显增高(P<0.01)。结论�Objective To investigate the effects of treadmill exercise on the motor function and mammalian target of rapamycin(mTOR)signal pathway in motor cortex of adult mice with spinal cord injury.Methods Thirty C57BL/6J mice were randomly divided into sham group,model group and treadmill exercise group(10 each).All mice received pre-training for 3 days,and those in model group and treadmill exercise group were crushed with C_(5) after pre-training in dorsal cortico-spinal tract,left cortico-spinal tract and rubro-spinal tract.The lamina was removed without damaging the spinal cord in sham group.Mice in treadmill exercise group began to run on the platform 1 week after injury,5 days every week for 4 weeks.The motor function recovery was assessed with Basso Mouse Scale(BMS),horizontal ladder and cylinder rearing tests.The expression of insulin-like growth factor 1(IGF-1),brain-derived neurotrophic factor(BDNF)and the phosphorylated level of tyrosine kinase receptor B(TrkB),insulin-like growth factor 1 receptor(IGF-1R),protein kinase B(Akt),and ribosomal S6 protein(S6)in motor cortex of mice were detected by Western blotting.The activation of cortical mTOR pathway was evaluated with immunofluorescence staining to detect the phosphorylated level of S6 in motor neurons.Results After injury,the BMS score of mice in model group and treadmill exercise group decreased briefly(P<0.0001),and recovered back to baseline level within 7 days.Compared with sham group,the error rate of left forelimb and left hindlimb increased(P<0.001)both in model group and treadmill exercise group 3 days,1 week,3 weeks and 5 weeks after injury.Compared with model group,the error rate of both left forelimb and left hindlimb decreased(P<0.001)in treadmill exercise group 3 and 5 weeks after injury.Compared with sham group,the utilization rate of left forelimb decreased(P<0.0001)both in model group and treadmill exercise group 3 days and 1 week after injury;and 3 and 5 weeks after injury,the utilization rate of left forelimb was still lower in model group

关 键 词：跑台运动 哺乳动物雷帕霉素靶蛋白信号通路 脊髓损伤 神经营养因子 运动功能 

分 类 号：R493[医药卫生—康复医学]