Experimental Study Of Effects Of Hypoxia Alone And Training Combined On Skeletal Muscle

Objective: Study the effects of hypoxia alone and training combined on skeletal muscle. To investigate the best method of training in hypoxia.Methods: 40 SD male rats were divided randomly into four groups: normoxia quiet group(A), normoxia training group(B), hypoxia quiet group(C) and hypoxia training group(D). The two hypoxia(C,D) groups were placed in hypoxic tent everyday from 8am to 5pm, and the two training groups(B,D) run on the treadmill with 25m/min, 30min everyday. In the acute and chronic period (3 days and 14days), inspect the rats body weight, serum concentration of A, CK-MM and LDH5, NO concentration in gastrocnemius muscle, MDA and SOD concentration in mitochondria of gastrocnemius muscle. Observe the changes of the gastrocnemius muscle cell's ultrastructure through the electron microscope. The express of the mRNA of VEGF were detected by means of polymerase chain reaction.Results: The loss of weight of rats in hypoxia quiet group compared with normoxia quiet group was significant. Morphologic changes of gastrocnemius muscle cell in hypoxia quiet group within acute period could be seen under electron microscope, such as augmentation of mitochondria volume and intracristal space. In chronic period, atrophy of muscle fibers can be seen, and mitochondria appeared swelling and cristaelysis. Serum concentration of CK-MM, LDH5 and MDA in gastrocnemius muscle were higher compared with others groups, while training in hypoxia could prevent it. Serum concentration of A was heighten in hypoxia and training conditions. The NO concentration in gastrocnemius muscle was raised in training groups. The express of the mRNA of VEGF was up-regulated in either hypoxia and training groups, in which the two conditions hadjoint action.Conclusions: The rats in hypoxia quiet group display various inadaptations such as loss of weight, atrophy of muscle fibers and breakdown of muscle mitochondria. While hypoxia combined training not only could prevent it, but also produce some optimum changes such as body weight gain, muscle fibers hyperplasia and vascular proliferation. The causes of above differences maybe concerned with the changes of neuroendocrine and immunological function regulated by training, at the same time some neuromediators also play a part in. So hypoxia combined training could promote the accustomization with highland.