Effect of electro-acupuncture on substance P, its receptor and corticotropin-releasing hormone in rats with irritable bowel syndrome.
OBJECTIVE
To investigate the effect and mechanism of electro-acupuncture (EA) at ST25 and ST37 on irritable bowel syndrome (IBS) of rats.


METHODS
A total of 21 male Sprague-Dawley rats were randomly divided into normal group, model group and EA group. A rat model of IBS was established by constraining the limbs and distending the colorectum of rats. Rats in EA group received bilateral EA at ST25 and ST37 with a sparse and intense waveform at a frequency of 2/50 Hz for 15 min, once a day for 7 d as a course. Rats in normal and model groups were stimulated by distending colorectum (CR). An abdominal withdrawal reflex (AWR) scoring system was used to evaluate improvements in visceral hypersensitivity. Toluidine blue-improved method, immunohistochemistry and radioimmunoassay were used to observe mucosal mast cells (MC), changes of substance P (SP) and substance P receptor (SPR) in colon and change of corticotropin-releasing hormone (CRH) in hypothalamus.


RESULTS
The threshold of visceral sense was significantly lower in model group than in normal group, and significantly higher in EA group than in model group. The number of mucosal MC was greater in model group than in normal group and significantly smaller in EA group than in model group. The CRH level in hypothalamus of rats was significantly higher in model group than in normal group, which was remarkably decreased after electro-acupuncture treatment. The SP and SPR expression in colon of rats in model group was decreased after electro-acupuncture treatment.


CONCLUSIONS
EA at ST25 and ST37 can decrease the number of mucosal MC and down-regulate the expression of CRH in hypothalamus, and the expression of SP and SPR in colon of rats with IBS.
Ma
Xiao-Peng
XP
Shanghai Institute of Acupuncture-Moxibustion and Meridian, Shanghai 200030, China.
Tan
Lin-Ying
LY
Yang
Yun
Y
Wu
Huan-Gan
HG
Jiang
Bin
B
Liu
Hui-Rong
HR
Yang
Ling
L
D000818:Animals; D003106:Colon / Q000378:metabolism / Q000473:pathology; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D004195:Disease Models, Animal; D015671:Electroacupuncture / Q000379:methods*; D007031:Hypothalamus / Q000378:metabolism; D043183:Irritable Bowel Syndrome / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008407:Mast Cells / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*
D018040:Receptors, Neurokinin-1; D013373:Substance P; D003346:Corticotropin-Releasing Hormone