| 1. ObiectiveObesity, a serious threat to human health, is caused by unhealthy lifestyle. Therefore, how to control the weight becomes the focus and difficulty of researches at present. The study found that hypoxia and exercise both play a role in weight control and enhance autophagy in skeletal muscle mitochondria. This research, taking obese animals of high fat diet as experimental model, probes to analyze its mechanism by observing hypoxic exercise’s influence on the weight control of obese rats and on the autophagy in skeletal muscle mitochondria, and to provide scientific basis for public exercising and losing weight. 2. MethodsIn order to build obesity model, we purchased 200 3-week-old SD rats which have no obvious difference in body weight before random grouping. Then we choose randomly 20 rats as normal diet group and 180 rats as high-fat diet group and feed them for 12 weeks. We consider this model successful with such a phenomenon that the average weight of rats in high fat diet group is 20 percent higher than that of rats in normal diet group. To classify equally these 40 rats selected from high fat diet group into four groups, namely normoxic sedentary group, normoxic exercise group, hypoxia sedentary group, hypoxia exercise group and to train them for four weeks. After 24 hours from the last training, to kill these rats and measure the relative expression of blood fat and corresponding autophagy by collecting blood sample from abdominal cavity as well as gastrocnemius meat. 3. Results 1)Variations in rats body weight, Lee’s index and fat/weight ratioCompared with normoxic sedentary groups, normoxic exercise group and the hypoxia sedentary group showed no obvious variations in body weight, Lee’s index(p>0.05), but fat/weight ratio decreased significantly(p<0.05). Hypoxic exercise group enjoys a significant decrease in weight, Lee’s index and body fat ratio(p<0.01); Compared with normoxic exercise group, hypoxic exercise group has a great decrease in body weight(p<0.05) and in Lee’s index(p<0.01), but no significant changes come to fat/weight ratio; compared with hypoxia sedentary group, hypoxic exercise group experiences an obvious decrease in weight and in Lee’s index(p<0.01), but no significant changes happen in fat/weight ratio. 2) Changes of rats’ blood lipid.Compared with normoxic sedentary group, the TC, TG and LDL-C of normoxic exercise group decreased significantly(p<0.05), however HDL-C shows the opposite trend(p<0.05). A large decrease is found in TC, TG and LDL-C of hypoxia exercise group(p<0.01), but a significant increase is found in HDL-C(p<0.01); Hypoxia sedentary group had no significant indexes change.Compared with normoxic exercise group, hypoxic exercise group showed no significant change; Compared with hypoxia sedentary group, TC, TG of hypoxic exercise group decreased very significantly(p<0.01), but HDL-C and LDL-C have no significant change. 3) Autophagy-related gene expression in each groupCompared with normoxic sedentary group, in normoxia exercise group, autophagy-related genes Beclin-1, P62, LC3 showed a small increase. But in hypoxia sedentary group and hypoxia exercise group, autophagy-related genes Beclin-1, P62, LC3 all experienced a very significant increase(p<0.001); Compared with normoxic exercise group, autophagy-related genes Beclin-1, in hypoxic exercise group increased largely(p<0.01) and P62 and LC3 raised extremely obviously(p<0.001); hypoxia sedentary group and hypoxia exercise group showed no obvious change in terms of autophagy-related gene expression. 4 Conclusion1) Under hypoxic and normoxic conditions, sports can promote lipid metabolism in rats to reduce the risk of atherosclerosis and cardiovascular disease.2) Normoxic and hypoxic exercise both contribute to losing weight, and hypoxic exercise has the more obvious effect.3) Hypoxia exercise can significantly improve the amount of relative expression of autophagy genes and promote autophagy to maintain homeostasis within the body’s cells. |
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