ABSTRACT
BACKGROUND: Balanced diet and scientific exercise are generally accepted as safe, effective and economical body mass management interventions. However, exercises sometimes increase the appetite of dieters. Combining hypoxic environment stimulation with aerobic exercise intervention may achieve the best effect on weight loss. As the central part of the body that regulates food intake and energy balance, the hypothalamus is concerned about the relationship between its regulating factors and the pathogenesis of obesity. OBJECTIVE: To observe the levels of nesfatin-1 and ghrelin in the hypothalamus of obese rats, so as to explore the neuroendocrine mechanisms of feeding and body mass by hypoxia and/or exercise. METHODS: Sixty Sprague-Dawley male rats with alimentary obesity were divided into six groups: quiet group, aerobic exercise group, 16.3% hypoxia quiet group, 16.3% hypoxic exercise group, 13.3% hypoxia quiet group and 13.3% hypoxic exercise group. A low-oxygen generator was used to create hypoxia environment at a volume fraction of 16.3% oxygen and 13.3% oxygen. Under hypoxia environment, the rats were continuously fed with high-fat food, and subjected to a treadmill exercise, 20 m/min (0° slope), 40 min/d, 5 days per week for 8 continuous weeks. Body mass and food intake were recorded, and Lee’s index was calculated. Levels of nesfatin-1 and ghrelin in the rat hypothalamus were measured after intervention by means of ELISA kit. RESULTS AND CONCLUSION: (1) The body mass and Lee’s index after intervention: the effect of simple hypoxic environment stimulation on body mass and Lee’s index of rats was not as obvious as that of simple aerobic exercise stimulation. When hypoxic environment was combined with exercise, the effect was better than that of single stimulation. (2) Daily food intake during the intervention period: The daily food intake remained stable in the normoxic quiet group, and decreased in all other groups decreased, especially in the 16.3% hypoxic exercise group and 13.3% hypoxic exercise group. (3) Levels of nesfinin-1 and ghrelin in the hypothalamus: hypoxia combined with exercise could change nesfinin-1 levels in the hypothalamus of rats, and the nesfinin-1 level was highest in the 13.3% hypoxic exercise group. Exercise or hypoxia alone could affect the ghrelin level in the hypothalamus of rats, and the effect of single exercise stimulation was better than that of single hypoxia stimulation. Moreover, the combination of exercise and hypoxia made a further reduction in the ghrelin level. (4) Bivariate analysis of variance: Body mass and ghrelin level were affected by exercise; body mass, Lee’s index and food intake were affected by O2 concentration; and body mass, nesfinin-1 and ghrelin levels were affected by exercise×O2 concentration. These findings indicate that 8-week hypoxic exercise may decrease the rats’ food intake, inhibit the increase of body mass and reduce the Lee’s index by regulating nesfinin-1 and ghrelin levels in the hypothalamus, but the specific mechanism is not clear.