[Electroacupuncture up-regulated arcuate nucleus alpha-MSH expression in the rat of diet-induced obesity]
Derun Tian1, Xiaodong Li, Dongbin Niu
1Neuroscience Research Institute, Peking University, Beijing 100083.
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 immumohistochemistry.
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 alpha-melanocyte-stimulating hormone (alpha-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 alpha-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 alpha-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 alpha-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 alpha-MSH, which inhibits food intake, resulting in a decrease of body weight.
