[Electroacupuncture up-regulated arcuate nucleus alpha-MSH expression in the rat of diet-induced obesity].
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.


CONCLUSIONS
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.
Neuroscience Research Institute, Peking University, Beijing 100083.
Derun
D
Tian
Xiaodong
X
Li
Dongbin
D
Niu
Yushun
Y
Shi
Jaw-Kang
JK
Chang
Jisheng
J
Han
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D001835:Body Weight; D004032:Diet; D015671:Electroacupuncture; D007031:Hypothalamus / Q000378:metabolism; D009765:Obesity; D051381:Rats; D015854:Up-Regulation; D000521:alpha-MSH / Q000378:metabolism*
D000521:alpha-MSH