Muscle tissue adaptations to hypoxia.
Muscle tissue adaptations to hypoxia.
复制标题
DOI：
--
复制
发表时间：
2001-09
期刊：
影响因子：
--
通讯作者：
H. Hoppeler;M. Vogt
中科院分区：
文献类型：
--
作者：
H. Hoppeler;M. Vogt
本文就低氧对人体骨骼肌组织的影响作一综述。早期报道认为，作为高原暴露的主要生理应激，慢性缺氧本身可能对肌肉的氧化能力和毛细血管功能产生积极的影响。然而，现在已经证实，持续暴露在严重的低氧环境中对肌肉结构有不利影响。对骨骼肌结构的短期影响可以很容易地观察到在2个月的急性暴露于严重缺氧，例如在典型的喜马拉雅登山探险期间。在长期居住在高海拔地区(例如，拉巴斯，海拔3600-4000米)的人身上，显示出肌肉组织的各种表型延展性。此外，有一些证据表明，藏族和确川人等高海拔人群对低氧具有遗传适应能力，他们世代生活在海拔3500米以上的环境中。在所有这些情况下，肌肉对低氧适应的标志是肌肉氧化能力的下降伴随着有氧工作能力的下降。在运动训练中，局部组织缺氧被认为是肌肉组织的一种重要的适应性应激，因此这些结果似乎与直觉相反。因此，已经进行了研究，受试者只在运动过程中暴露在低氧环境中。在这种情况下，永久性低氧暴露和其他与高海拔暴露相关的混杂变量的潜在负面影响可以避免。低氧训练在分子水平上导致低氧诱导因子-1(HIF-1)调节亚单位的上调。可能由于HIF-1的这种上调，肌红蛋白、血管内皮生长因子和糖酵解酶(如磷酸果糖激酶)的mRNAs水平以及线粒体和毛细血管密度在低氧依赖的方式下增加。功能分析显示，V(O(2)max)(在海拔测量时)对最大功率输出和瘦体重有积极影响。除了低氧训练对运动成绩的积极影响外，最近的一些迹象表明，低氧训练对心血管疾病的危险因素有积极的影响。
This review reports on the effects of hypoxia on human skeletal muscle tissue. It was hypothesized in early reports that chronic hypoxia, as the main physiological stress during exposure to altitude, per se might positively affect muscle oxidative capacity and capillarity. However, it is now established that sustained exposure to severe hypoxia has detrimental effects on muscle structure. Short-term effects on skeletal muscle structure can readily be observed after 2 months of acute exposure of lowlanders to severe hypoxia, e.g. during typical mountaineering expeditions to the Himalayas. The full range of phenotypic malleability of muscle tissue is demonstrated in people living permanently at high altitude (e.g. at La Paz, 3600-4000 m). In addition, there is some evidence for genetic adaptations to hypoxia in high-altitude populations such as Tibetans and Quechuas, who have been exposed to altitudes in excess of 3500 m for thousands of generations. The hallmark of muscle adaptation to hypoxia in all these cases is a decrease in muscle oxidative capacity concomitant with a decrease in aerobic work capacity. It is thought that local tissue hypoxia is an important adaptive stress for muscle tissue in exercise training, so these results seem contra-intuitive. Studies have therefore been conducted in which subjects were exposed to hypoxia only during exercise sessions. In this situation, the potentially negative effects of permanent hypoxic exposure and other confounding variables related to exposure to high altitude could be avoided. Training in hypoxia results, at the molecular level, in an upregulation of the regulatory subunit of hypoxia-inducible factor-1 (HIF-1). Possibly as a consequence of this upregulation of HIF-1, the levels mRNAs for myoglobin, for vascular endothelial growth factor and for glycolytic enzymes, such as phosphofructokinase, together with mitochondrial and capillary densities, increased in a hypoxia-dependent manner. Functional analyses revealed positive effects on V(O(2)max) (when measured at altitude) on maximal power output and on lean body mass. In addition to the positive effects of hypoxia training on athletic performance, there is some recent indication that hypoxia training has a positive effect on the risk factors for cardiovascular disease.