Electroacupuncture up-regulated arcuate nucleus ?-MSH expression in the rat of diet-induced obesity / 北京大学学报(医学版)

ABSTRACT

Objective: To investigate the effect of electroacupuncture (EA) on rat with diet induced obesity (DIO) and to explore the possible neurochemical mechanisms using the technique of immumohistochemisty. Methods:To establish DIO rat model by feeding the animals with high fat diet for 14 weeks. DIO rats were randomly divided into 4 groups (1) 2Hz EA group, (2) 100Hz EA group, (3) restrain control group,(4) diet resistance (DR) group,(5) DIO group and (6) normal control group. EA treatment (1) The acupoints used were Zusanli and Sanyinjiao on both legs. (2) The intensities of stimulation were 0.5, 1.0 and 1.5mA for 10 mins each. EA treatment was administered 3 times per week. Food intake and body weight were measured daily for 4 weeks. (3) The changes of the expression of ? melanocyte stimulating hormone (? MSH) in the hypothalamic arcuate nucleus (ARC) were measured with immunohistochemical semiquantitative analysis. Results: (1) The food intake and body weight of 2 Hz EA group and 100 Hz EA group were decreased significantly compared with the restrain control group and DIO group. (2) The number of ? MSH positive cells in hypothalamic ARC in 2 Hz EA and 100 Hz EA group was significantly higher than that in restrain control group and DIO group. The number of ? MSH positive cells in hypothalamic ARC in DIO group is significantly lower than those in DR group or normal control group. Conclusion: A decrease of ? MSH level in hypothalamus may be associated with diet induced obesity. The therapeutic effect on obesity produced by EA may be accounted for by the stimulation of pro opio melanocortin neurons in hypothalamic ARC to release ? MSH, which inhibits food intake , resulting in a decrease of body weight.