| We used SD Sprague-Dawley) rats as our experiment subjects, and used high-fat diet for obesity model, in order to investigate the effects of different hypoxic exposure groups on weight change in obese rats and whether were these effects persistent or not. Then we also investigate the adjustment mechanism of the weight change from the level of hormones, biochemical and neuroendocrine, which was caused by hypoxic exposure.The obese rats were randomly divided into three groups, two of them were exposed to simulated3km and5km altitude (3km:Partial pressure of oxygen110mmHg, the content of atmospheric oxygen about14.4%;5km:Partial pressure of oxygen85mmHg, the content of atmospheric oxygen about11.1%), the rest group was control group (the average altitude about60m, Partial pressure of oxygen156mmHg, the content of atmospheric oxygen about20.9%). Hypoxia exposure group exposed to hypoxia for10days, and the rats were fed20days under the control altitude after hypoxia exposure.We recorded weight and food intake of the rats during the hypoxia and restoration. Calculate the relevant organs index of rats (Liver, kidney, spleen, adrenal, pituitary). We determined the rat serum leptin, insulin and hypothalamus ARC NPY by Elisa. And Glucose, total cholesterol and triglyceride levels were determined by physiological and biochemical kits, The experimental results are as follows:1. Hypoxic exposure significantly decreased body weight and food intake of rats; In the stage of early restoration, the body weight of rats increased but still had significant differences compared with the control group, the rest stage of restoration remained a decreasing situation.2. Hypoxic exposure significantly increased the adrenal index of obese rat, had no significant impact on the Liver, kidney, spleen and pituitary index; Hypoxic exposure significantly decreased the Liver index of normal rat; during the restoration, there had no significant impact on the Liver, kidney, spleen, adrenal and pituitary index both in obese and normal rats. 3. Hypoxic exposure significantly decreased glucose, total cholesterol and triglyceride levels of rats (Obese and normal rats); during the restoration, there had no significant impact on glucose, total cholesterol and triglyceride levels.Hypoxic exposure significantly decreased the level of plasma corticosterone in the obese rats, and there had no significant impact on the level of plasma corticosterone in the obese rats; there had no significant impact on the level of plasma corticosterone in the normal rats during the stage of hypoxic exposure and restoration.4. Hypoxic exposure significantly increased the level of leptin and insulin in obese and normal rats. The level of leptin and insulin in obese rats still significantly increased but had no significant change on normal rats during the restoration.5. Hypoxic exposure significantly decreased the level of hypothalamus ARC NPY in obese and normal rats; the level of hypothalamus ARC NPY in obese rats still significantly decreased and maintained at a relatively low level but had no significant change on normal rats during the restoration.In summary:hypoxic exposure significantly increased the level of leptin and insulin and decreased the level of hypothalamus ARC NPY in rats. So leptin and insulin may pass the blood-brain barrier and reach the rat hypothalamus ARC, making NPY reduce and inhibiting eating; Elevated insulin may increase the organization energy consumption and reduce the weight. During the restoration, serum leptin and insulin still had higher level in obese rats, which inhibited eating and increase energy consumption, that made the weight decrease; But serum leptin and insulin went back to normal level in normal rats, and the level of hypothalamus ARC NPY kept stable, food intake and body weight gradually returned to normal.So, hypoxia affects the body weight of rats by reducing eating and increase energy consumption; hypoxia has more significant and lasting effects on the body weight of obese rats. |
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