| Obesity or overweight is defined as metabolic disease, caused by abnormal and excessive fat storing that leads to health risks, which caused by disturbance of energy intake and metabolism. It’s related to heredity, nutrition, physical activity and endocrine function. The total prevalence of overweight and obese Chinese adults in 2010 was 42.6%. Given this situation, China currently has the highest number of obese and overweight people, which remains depressingly.Active lifestyle helps to remove and reduce excess fat accumulation. However, lacking of physical activity at present is the forth death risk factor (account for 6 percent of global death). Otherwise, physical inactivity is the main cause of 21-25%breast and colon cancer,27% diabetes and 30% ischemic heart disease.Orexin is a central neuropeptide that was found to homeostatically coordinate a diverse range of physiological responses, such as feeding behavior, physical activity and energy expenditure in 1998, which has been a hotspot in research of obesity preventing.For now, research on the association between orexin and physical activity and its mechanism are little. Therefore, this study focuses on the association between orexin-A and physical activity in Chinese overweight and obese population. Further study on diet-induced mice will be conducted to observe the effect of physical activity intervention on expression and regulation of orexin-A by detecting related mRNAs in hypothalamus of mice, which will provide new theoretic basis for obesity preventing. ObjectivesTo measure the amount of physical activity (PA) among obese adults, investigate the association between plasma orexin-A level and physical activity patterns, and explore the effect of orexin on the prevention and control of obesity. Methods Clinical research Interviews were conducted in participants who accorded with the inclusive criteria using a survey that included socio-demographic variables. The International Physical Activity Questionnaire (IPAQ-long version) was used to measure physical activity. Plasma orexin-A content was measured by ELISA testing.Experimental research Diet induced obesity mice were built and estimated. Fasting glucose was measured by glucose meter. TG, TC, LDL-C, and HDL-C were determined by enzymatic methods. The relative expression of HCRT mRNA, OX1RmRNA and OX2RmRNA were measured by real-time polymerase chain reaction.Clinical research The average level of orexin-A was 85.34±42.85 ng/L in the obese group, 97.38±36.72 ng/L in the overweight group and 106.56±52.09 ng/L in the control group, which was significantly different (p<0.05). The concentration of plasma orexin-A correlated to the total PA, moderate PA and walking PA in all three groups (p<0.001).Experimental research After mice model building, the weight of group C, OR and OR-R were 31.36±1.06g,36.86±2.09g and 30.74±0.95g respectively,which showed significantly difference(p<0.001). Lee’s index, FC, fasting glucose, TG, TC and LDL-C were increased remarkablely in OR mice compared to the control group (p<0.05) while HDL-C was decreased (p<0.05). The intervention of physical activity led plasma orexin-A level of mice in E group increased to 96.19±22.36ng/L, compared to 36.67±5.18ng/L in NE group (p<0.001). The expression of HCRTmRNA,OX2RmRNA in E group were elevated significantly when compared to group NE (p<0.001) and both lower than that in C group, however(p<0.05). The content of OX1RmRNA had no significant difference in group E and NE (P>0.05). Liner correlation analysis showed that the expression of HCRT mRNA correlated to plasma orexin-A level, TG, HDL-C, OXlRmRNA positively and weight, fat mass, Lee’s index, FC negatively. The expression of OX1RmRNA only positively correlated with HCRT mRNA.OX2RmRNA content only correlated with FC negatively.1. The plasma orexin-A level was associated with physical activity in obese and overweight people, including working, domestic work and walking physical activity.2. A high orexin-A level was related to moderately active movement in living habits.3. The higher orexin tone is an endogenous factor that predicts physical activity, and in doing so improve BMI in energy expenditure aspect.4. Physical activity helped to increase the level of OXA by improving the expression related receptors, especially OX2R. |
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