| Objective: To Study the effects of hypoxia and complex training under hypoxia on skeletal muscle, weight, and the change of hypoxia inducible factor-1 of the rat, and to make a study of the best method to improve the adaptation of the body to hypoxia and the possible mechanism.Methods: 80 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). Set up running model by training normoxia training group(B) and hypoxia training group(D) on the treadmill at 25m/min and for 30min everyday. Besides, the two hypoxia groups (C,D) were placed in hypoxic tent everyday from 8am to 8pm. Test the weights of the rats, gastrocnemius and the expression of HIF-1 separately after 3 days(acute period), 7 days, 10 days and 14 days(chronic period). The changes of ultrastructure in the cells of gastrocnemius were observed by the electron microscope, and the expression of HIF-1 was studied by Surface-enhanced Laser Desorption/Ionization (SELDI) and real-time fluorescence quantitative polymerase chain reaction (FQ-PCR). The factorial analysis was used to see the relations among oxygen, training, time and the results above.Results: Compared with hypoxia quiet group(C), the weights of the rats innormoxia quiet group(A), normoxia training group(B) and hypoxia training group(D) raised significantly for different extent (p<0. 05). Morphologic changes, such as augmentation of mitochondria volume and intracristal space, occurred in the cells of gastrocnemius muscle after the acute period, which could be seen in hypoxia quiet group under electron microscope. Besides, the atrophy of muscle fibers, swelling and cristaelysis of mitochondria were seen in the same group after the chronic period. However, the hyperplasia of muscle fibers and capillary vessel, the normal structure of texture and muscle fibers were seen in the hypoxia training group. The expression of HIF-1 was up-regulated whether training or not under hypoxia, which was more obvious when it was tested later. While, the expression of HIF-1 was also up-regulated when the rats ran both in hypoxia and normoxia, especially the former when the two factors(hypoxia and training) had joint action.The result suggested that HIF-1 seldom expressed in normoxia quiet group, but its expression was up regulated after the acute period when the rats were trained in both hypoxia and normoxia and the difference was significant. When the rats were trained in normoxia, the expression of HIF-1 tend to descend till normal after two weeks, which suggested that the training at this level could not result in the responsion to hypoxia. In our study, the longer the hypoxia continued, the more HIF-1 expressed, which may mean that hypoxia combined with training play a more important role in inducing the expression of HIF-1 than hypoxia or training alone. The result of factorial analysis suggested an internal action among hypoxia, time and training. The expression of HIF-1 ascended as the time of hypoxia prolonged.Conclusions: Hypoxia combined with training play an important role in the promotion of accustomization to hypoxia. HIF-1 played a positive role in the same process and the mechanism of which may lie in that induction and promotion might benefit the transcription and translation of the proteins in favor of adaptation, whichcould keep the cells alive in hypoxia by adding energy to the cells of promoting the supply of oxygen to the cells and tissues. HIF-1 might be guideline of the hour and intension of the training, and the level of its expression correlated closely with the load of training, which could be used to estimate the training load and the endurance of body to it. Therefore, we need to study the quantized relationship between the expression of HIF-1 and the training load, and to use the level of expression of HIF-1 to estimate the training intension of athletes and soldiers in order to offer a academic basis to set up an scientific training scheme. |
PDF Full Text Request