Takahashi H, Asano K, Nakayama H
Faculty of Integrated Arts & Sciences, Hiroshima University.
Appl Human Sci. 1996 May;15(3):111-4. doi: 10.2114/jpa.15.111.
The adaptive response of oxidative enzyme activity in the skeletal muscle to training in normoxic and in normobaric hypoxic training was studied. Forty male Wistar rats were divided into 4 groups: normoxia + sedentary (NS, n = 10); hypoxia + sedentary (HS, n = 10); normoxia + training (NT, n = 10); and hypoxia + training (HT, n = 10). Rats in the NT group ran on a treadmill for 30 min a day at 20-30 m.min-1, 4 days a week for 10 weeks in normoxia. Rats in the HT group performed the same training protocol as NT in an ambient FIO2 decreased to 12%. HS rats were exposed to hypoxia in the same degree, duration and frequency as HT without exercise. After the training period, the soleus and the plantaris muscles were removed, and the activities of mitochondrial enzymes, malate dehydrogenase (MDH) and 3-hydroxyacyl-CoA dehydrogenase (HAD) were measured by a spectrophotometer. The normoxic training did not increase MDH or HAD activities, in either the soleus or the plantaris. This absence of change in mitochondrial enzyme activities is considered to be the results of inadequate stimulus of training, including a relatively low amount of exercise. On the other hand, the hypoxic training enhanced the MDH activity in the soleus by 17.5% compared with NS (P < 0.01) and by 20.5% compared with HS (P < 0.01). Also in the plantaris, the MDH activity in HT was higher than that in HS (15.7%, P < 0.05). These findings suggest that even moderate training by which enzyme activity is not increased under normoxic conditions can enhance the oxidative capacity in the skeletal muscle when the training is performed in a hypoxic environment.
研究了骨骼肌氧化酶活性在常氧训练和常压缺氧训练中的适应性反应。40只雄性Wistar大鼠分为4组：常氧+久坐不动组（NS，n = 10）；缺氧+久坐不动组（HS，n = 10）；常氧+训练组（NT，n = 10）；缺氧+训练组（HT，n = 10）。NT组大鼠在常氧环境下，每周4天，每天在跑步机上以20 - 30米/分钟的速度跑30分钟，持续10周。HT组大鼠在环境氧分压降至12%的条件下进行与NT组相同的训练方案。HS组大鼠在与HT组相同的程度、持续时间和频率下暴露于缺氧环境，但不进行运动。训练期结束后，取出比目鱼肌和跖肌，用分光光度计测量线粒体酶苹果酸脱氢酶（MDH）和3 - 羟酰基辅酶A脱氢酶（HAD）的活性。常氧训练未增加比目鱼肌或跖肌中的MDH或HAD活性。线粒体酶活性没有变化被认为是训练刺激不足的结果，包括运动量相对较低。另一方面，与NS组相比，缺氧训练使比目鱼肌中的MDH活性提高了17.5%（P < 0.01），与HS组相比提高了20.5%（P < 0.01）。在跖肌中，HT组的MDH活性也高于HS组（15.7%，P < 0.05）。这些发现表明，即使是在常氧条件下不会增加酶活性强度的适度训练，在缺氧环境中进行时也能提高骨骼肌的氧化能力。
