Establishment Of Diet Induced Obesity Model In Rats And Study On The Mechanism Of Obesity Treated By Electroacupuncture

Obesity is becoming a modern disease that is threatening human health and its pathogenesis is extremely complex. At present, no safe and effective drugs with few side effects can treat obesity. Many experimental and clinical studies demonstrated that traditional acupuncture was effective on obesity treatment. Reported experiments demonstrated that electric stimulation with special frequency could modulate the expressions of different neuropeptides. So we deduced that electroacupuncture (EA) could also modulate the expressions of neuropeptides related with food intake and then cure the obesity, too.In our experiment some of the overweight and obese volunteers were treated with Han's acupoint nerve stimulator (HANS) regularly and their weight changes were recorded and analyzed. Also based on the establishment of diet induced obesity (DIO) model in rats successfully the DIO rats were treated by HANS for 4 weeks (12 times), at the same time, the weights and food intakes of DIO rats were recorded. The expressions of neuropeptides in hypothalamus and plasma were determined by immunohistiochemistry and enzyme-linked immunosorbent assay (ELISA) respectively. The mechanism of the acupuncture on obesity treatment was discussed, too.Results:1. After 16 overweight and obese volunteers without restricting their food intake were treated with 2 Hz EA by HANS their weights declined gradually. At the end of the twelfth week the weights of volunteers decreased by (2.04+0.33) kilograms and weight percentages decreased by (2.64+0.41) % (P < 0.001).After 4 weeks' disruption the volunteers' weights increased. However, whenthey were treated by HANS for 8 weeks again their weights and weight percentage decreased by (2.39+0.63) kilograms and (3.18+0.83) % respectively. Compared with previous treatment, the body weights and the body mass indexes (BMI) of the.volunteers decreased significantly (P < 0.001). 2. Establishment of DIO model in rats successfully: the average percentages of the body weights of the DIO rats raised with high energy diet for 14 weeks was 136.1% compared with the normal control rats' one (P < 0.001).3. The plasma cholesterol, triglyceride and melanin concentrating hormone (MCH)of the DIO rats all exceeded apparently the ones of the normal rats (P < 0.01, P < 0.05 and P < 0.05, respectively) and the plasma a-melanocyte stimulating hormone (a-MSH) of the DIO rats was lower than the one of the normal rats (P< 0.05).4. Compared with the restriction rats and the DIO rats the volume of food intake andenergy intake of the rats treated with 2 Hz or 100 Hz EA decreased obviously (P< 0.001) and their body weights decreased, too (P < 0.05).5. The results of immunohistiochemistry showed that the numbers of a-MSH positive cells in arcuate nucleus (ARC) of hypothalamus in the DIO rats were lower than the ones of the diet resistance (DR) rats and the normal rats. The numbers of a-MSH positive cells in ARC of the rats treated with 2 Hz or 100 Hz EA were higher than the ones of the DIO rats (P < 0.001) and the restriction rats (P < 0.01 and P < 0.05, respectively). There was no difference between the rats treated with 2 Hz and 100 Hz EA.Conclusions:1. Transcutaneous electric nerve stimulation (TENS) of 2 Hz is effective to control the body weight of the overweight and obese person and it would be more effective if cooperated with diet control and physical exercise.2. High-energy diet and / or decrease of a-MSH in ARC can result in obesity.3. There are high cholesterol, triglyceride and MCH levels and low a-MSH level inthe plasma of the obesity patient. High level of MCH and low level of a-MSH in plasma participate the development of obesity probably.4. One of the mechanisms of EA on treating obesity is probably that EA increasesthe release of a-MSH in ARC and then inhibits food intake, promotes energy expenditure and decreases the weight eventually.