[Effect of intermittent hypoxia on leptin and leptin receptor expression in obesity mice]

In order to explore the effect and underlying mechanism of hypoxia on body weight, the effect of intermittent moderate hypoxia on high-fat diet-induced obesity was observed in mice, and the role of leptin in hypoxic effect was identified. Healthy Kunming mice were divided randomly into 4 groups (n=20 in each group). The control group: the mice were fed normally under the normal oxygen pressure. Hypoxia group: the mice were fed normally, and given intermittent moderate hypoxia training. Obesity group: the mice were fed diet rich in fat and sugar under the normal oxygen pressure. Hypoxia + obesity group: the mice were fed diet rich in fat and sugar, and given intermittent moderate hypoxia training. After 40 d of feeding and training, the body weight of mice was determined, and the average increasing rate of body weight in each group was calculated and normalized with food intake. Meanwhile, plasma leptin level was measured with ELISA method, and fatty degeneration and leptin receptor expression in liver were observed by Sudan III staining and immunohistochemistry, respectively. The obesity mouse model was successfully established with increases in body weight, plasma leptin level and distribution of adipocytes in the liver. The average body weight and density of adipocytes in the liver in hypoxia and hypoxia + obesity groups decreased obviously, while plasma leptin level and leptin receptor expression in the liver were increased. It is suggested that intermittent moderate hypoxia reduces body weight through elevating plasma leptin level and/or enhancing leptin receptor expression in the liver.