缺血预处理对缺血骨骼肌收缩功能的影响

背景缺血预处理能有效提高骨骼肌缺血耐受性,减轻骨骼肌缺血再灌注期间的坏死范围,但缺血预处理对骨骼肌收缩功能的影响文献报道不多.目的探讨缺血预处理对骨骼肌缺血再灌注期间收缩功能的影响.设计以实验动物为研究对象的随机对照研究.单位华中科技大学同济医学院及解放军第二五二医院.材料实验地点为解放军第二五二医院中心实验室.选用健康雄性SD大鼠14只.方法采用大鼠后肢缺血再灌注模型,将14只大鼠随机分为对照组和实验组.对照组持续缺血4h,再灌注1 h;实验组缺血5 min,再灌注5 min,重复3次后,持续缺血4 h再灌注1h.测定缺血再灌注期间腓肠肌收缩功能变化及再灌注1 h后,血清磷酸激酶(CK),丙二醛和腓肠肌99锝m亚甲基二磷酸钠(99TcmMDP)吸收量变化.主要观察指标缺血预处理对腓肠肌收缩力及对血清CK,丙二醛及99TcmMDP吸收量的影响.结果实验组腓肠肌收缩力在缺血4h时为(14.32±5.05)g,再灌注1h时为(25.71±7.58)g,对照组分别为(0,4 73±2.05)g,两者相比差异有显著性意义(P＜0.05),实验组血清CK为(104.85±9.84)nkat/L,丙二醛为(3988.60±455.92)nmol/L,99TcmMDP吸收量为(56.0±8.1)mBq/g·mir,对照组CK为(136.36±14.50)nkat/L,丙二醛为(6542.90±536.72)nmol/L,99TcmMDP吸收量为(97.3±5.8)mBq/g·min,两者相比差异有显著性意义(P＜0.05,P＜0.01).结论缺血预处理能有效改善缺血再灌注期间骨骼肌的收缩力,减轻骨骼肌坏死程度.因此,缺血预处理对缺血骨骼肌的收缩功能具有保护作用.

Impacts of ischemic preconditioning on the contractile function of skeletal muscle

BACKGROUND: Ischemic preconditioning (IPC) can effectively improve the ischemic resistance of skeletal muscle and reduce the necrotic areas during ischemia-reperfusion; However, the impacts of IPC on contractile function of skeletal muscle during ischemia-reperfusion is unclear.OBJECTIVE: To investigate the effect of IPC on contractile function of skeletal muscle during ischemia-reperfusion.DESIGN: A randomized controlled study by employing experimental animals as subjects.SETTING: Tongji Medical College, Huazhong University of Science and Technology and the 252 Hospital of Chinese PLA.MATERIALS: The experiment was completed in the 252 hospital of Chinese PLA. Totally 14 healthy SD rats were involved.METHODS: A rat right hindlimb ischemic model was utilized, 14 SD rats were randomly divided into control group and experimental group. Control group: sustained ischemia for 4 hours and reperfusion of 1 hour. Experimental group: ischemia for 5 minutes and reperfusion for 5 minutes, after 3 cycles, ischemia for 4 hours and reperfusion for 1 hour continuously of IPC.The isometric twitch contractile force of the right gastrocnemius muscle was measured as a parameter indicating the muscle functional status during is chemia reperfusion. The changes of creatine kinase (CK), malondialdehyde (MDA) in blood sample and the uptake of 99Tcm-methylene diphosphonate (99TcmMDP) in skeletal muscle were measured after 1 hour of reperfusion.MAIN OUTCOME MEASURES: The impacts of IPC on contractile force of gastroenemius and serous CK, MDA and the uptake of 99TcmMDP.RESULTS: The muscle contractile force in the experimental group after four hours of ischemia was (14.32 ± 5.05) g or (25.71 ± 7.58) g after one-hour reperfusion, which was significantly higher than 0 g or (4. 73 ± 2.05) g of control group(P ＜0. 05). The serous levelsofCK [(104.85 ±9. 84) nkat/L], MDA [ (3 988.60 ± 455.92) nmol/L] and the uptake of 99TcmMDP [ (56.0± 8.1 ) mBq/g per minute] were significantly lower in the experimental group than control group [CK(136.36 ± 14.50) nkat/L, MDA (6 542.90±536.72)nmol/L, and 99TcmMDP (97.3 ±5.8) mBq/g per minute, P＜0.05, P ＜0.01].CONCLUSION: IPC can effectively ameliorate the contractile force of skeletal muscle and reduce the necrotic degree of skeletal muscle. Therefore, IPC has a protective effect on the contractile force of ischemic skeletal muscle.