【作者】 王维群；

【导师】 姜文凯；

【作者基本信息】 苏州大学 ， 体育教育训练学， 2007， 博士

【摘要】 研究目的:低氧训练是近年进展最快的训练学研究领域之一,但迄今为止对其生物学机理及应用范围尚存在较多空白或争议。骨骼肌对运动适应的主要表现之一——毛细血管的新生。骨骼肌在承受不习惯负荷时会出现运动性肌损伤(EIMD),其修复伴有毛细血管的新生,与大量的细胞因子有关,血管内皮细胞生长因子(VEGF)和碱性成纤维细胞生长因子(bFGF)在其中发挥着重要作用,而运动医学领域对两因子的研究尚处于初探阶段。本文采用组织学、分子生物学和免疫组化等技术,研究低氧和/或运动对大鼠腓肠肌VEGF和bFGF表达的影响程度和时间规律,探讨VEGF和bFGF在骨骼肌毛细血管新生和EIMD修复中的作用,丰富相应研究资料。研究方法:研究对象为雄性SD大鼠,采用急性和短期的单纯低氧、常氧和高住低练下不同强度的运动模型,急性运动性肌损伤模型。跟踪测试不同时间组下列指标:大鼠血清肌酸激酶和乳酸脱氢酶活性(全自动生化分析)、大鼠腓肠肌VEGF蛋白(Western blot、ELISA)、bFGE蛋白(免疫组化)、大鼠腓肠肌毛细血管密度(CD,免疫组化CD34)、大鼠腓肠肌毛细血管数与肌纤维数的比值(C/F)、大鼠腓肠肌结构观察(HE染色)。实验结果采用SPSS13.0统计软件进行分析。研究结果:1、本研究所得低氧、运动后大鼠体重、血清CK和LDH活性的结果与常规相符。2、低氧、常氧运动可诱导大鼠腓肠肌VEGF表达升高,反复缺氧将导致VEGF对缺氧不敏感。长时间中等强度的运动比间歇性的高强度运动诱导更多的VEGF表达。高住低练削弱了长时间中等强度运动诱导的VEGF表达,高住低练组表现出较强的运动能力。VEGF恢复和适应的速度由快向慢顺序为:低氧、高住低练、常氧运动。低氧和/或运动后大鼠腓肠肌VEGF蛋白表达属早期速发效应。3、低氧、常氧运动可诱导大鼠腓肠肌bFGF表达升高,反复缺氧将导致bFGF对缺氧不敏感。在一定范围内,运动诱导的骨骼肌bFGF表达的幅度随运动强度的增加而加大,且具有延迟性特征。长时间中等强度的高住低练比相应的常氧训练更能诱导bFGF表达,递增强度的高住低练削弱了高强度运动诱导的bFGF表达。低氧和/或运动后大鼠腓肠肌bFGF表达不是即时性的,属较长期的持续反应。4、在短期常氧训练和高住低练的第6d出现了毛细血管新生的情况,高住低练比常氧训练明显,长时间中强度训练比间歇性的高强度训练明显。低氧和/或运动诱导的VEGF和bFGF表达的时间规律是不一致的,但它们都参与了低氧和/或运动诱导的骨骼肌毛细血管新生。5、VEGF和bFGF的过量表达贯穿EIMD修复的全过程,bFGF升高的幅度大于VEGF,两因子协同参与EIMD修复。研究结论:本研究采用的运动模型是有效的。本研究以VEGF和bFGF蛋白水平为观察点,揭示了低氧和/或运动对大鼠腓肠肌VEGF和bFGF表达影响的规律。VEGF和bFGF参与了骨骼肌毛细血管新生和EIMD修复。短期的高住低练能提高大鼠骨骼肌对长时间中等强度和间歇性高强度运动的适应能力。低氧和/或运动对不同类型肌纤维VEGF和bFGF表达影响的研究具有广阔的前景。更多还原

【Abstract】 Objective: Investigation of hypoxia training becomes one of the fastest-progress research areas all around the world in these years, but there are lots of unknown things and arguement in its biologic mechanism and application. Capillary neogenesis is one of the main reflections of skeletal muscle’s adaptation to hypoxia and exercise, because exercise induced muscle damage(EIMD) will occur when skeletal muscle undertakes unaccommodated exercise, which reparation progress may be accompanied with capillary neogenesis possibly through many cytokines. Vascular endothelial cell growth factor (VEGF) and basic fibroblast growth factor (bFGF) are two of these cytokines which play important roles. However, the investigation of VEGF and bFGF is still the primary study process in the sports medicine field. Therefore, the present study was aimed to investigate the effects of hypoxia and/or exercise on the expression and time course of VEGF and bFGF in the rats’ gastrocnemius, and the effects of VEGF and bFGF on the capillary neogenesis and reparation of EIMD by histological, molecular biological and immunohistochemical technology.Methods: Male SD rats were used to establish the acute exercise muscle injury models and then applied to either acute or short-term exercise training with different intensity of pure hypoxia, normoxia as a simulation of "living high-training low". At the different time points, many parameters are measured, respectively including the serum creatine kinase and lactate dehydrogenase (automatic biochemistry analysis instrument), the expression of VEGF (Western blot、ELISA) or bFGF (immunohistochemistry), the capillary density (CD, CD34 immunohistochemistry) , the ratio of the capillary number to fiber number (C/F), microstructure of gastrocnemius (HE stain) in the gastrocnemius muscle. Experiment results were analysed by the SPSS statistics software package (13.0). Results: (1) The results from hypoxia, weight after training, the activity of the serum CK or LDH could be matched to common condition. (2) Hypoxia and normoxia exercise increased the expression of VEGF in the gastrocnemius, and the repeated hypoxia caused the insensitivity of VEGF to hypoxia. The exercise with long time and common intensity induced the higher level VEGF expression than exercise with intermittence strong intensity. The living high-training low weakened the expression of VEGF induced by long time normal intensity exercise, and the group had shown the better exercise ability. The VEGF recovery and adaptation was inverse with its extent of rise, the order from the fast to the slow was: hypoxia, the living high-training low, normoxia exercise. The expression of VEGF was the early and quick response of the gastrocnemius after hypoxia and/or exercise. (3) Hypoxia and normoxia exercise increased the expression of VEGF in the gastrocnemius, the repeated hypoxia caused the insensitivity of VEGF to hypoxia. The skeletal muscle expression of bFGF induced by exercise was positively correlated with exercise intensity in a certain range with the characteristic delayed onset. The living high-training low with long time moderate intensity induced the higher level of bFGF expression than the corresponding normoxia, The living high-training low to increase progressively weakened the bFGF expression induced by high intensity of exercise. After hypoxia and/or exercise, the bFGF expression in the gastrocnemius was the delayed response. (4) On the 6th day of the short-term normoxia exercise and the living high-training low, the blood capillary neogenesis happened, which was more obviously in the living high-training low exercise than normoxia exercise, and more obviously in the long time moderate intensity exercise than the high intensity of exercise. The VEGF and bFGF expression induced by hypoxia and/or exercise was kept in the different time points. (5) The increased expression of the VEGF and bFGF presented during the whole reparation of EIMD, and bFGF was higher than that of VEGF. Both VEGF and bFGF had the synergistic effect on the reparation of EIMD.Conclusions: The exercise model used in the study is valid. The study based on the investigation of the VEGF and bFGF protein level, has revealed the regularity of the gastrocnemius muscle expression of VEGF and bFGF influenced by hypoxia and/or exercise. Either VEGF or bFGF may play a role in the capillary neogenesis of skeletal muscle and the reparation of EIMD. The short-time living high-training low could enhance the adaptation ability to rats’ skeletal muscle to exercise with long-time and moderate intensity and exercise with intermittence strong intensity. There iswidely perspective of the study for hypoxia and/or exercise influencing VEGF andbFGF expression by different types of muscle fiber.更多还原