Effects of electroacupuncture on disorder of intestinal motility in a rat model of irritable bowel syndrome

Abstract

To investigate the effects of electroacupuncture (EA) on intestinal motility disorder in rats with irritable bowel syndrome (IBS) in order to provide experimental evidence for improving clinical treatment to IBS with EA. IBS was induced by inserting a balloon into the rectum of male Sprague-Dawley rats from their neonatal age (8th, 21st day after birth) and applying colorectal distention stimulation by inflating air into the balloon. Peristaltic wave (PW) was used to estimate intestinal motility. Rats were divided into 4 groups (n=6): normal group, untreated group, sham EA group and EA group. Acupoints of Zusanli (ST36) and Shangjuxu (ST37) in the hind limbs bilaterally were chosen for EA and sham EA treatment. Trains of dense-sparse frequencies (100 Hz and 2 Hz alternately) and intensity of 1, 2 and 3 mA (10 min for each) were applied for 30 min with each EA treatment while inserting similar needles without electrical stimulation was done as sham EA treatment. PW recorded for 30 min in normal and untreated groups respectively was taken as control values, while PW recorded after EA or sham EA treatment for 30 min was taken as responsive values. Frequency of PW was significantly increased in the untreated group as compared with that in the normal group (P<0.05), and decreased after 30-min EA treatment (P<0.05). There was no significant change in the PW of sham EA group as compared with the control group and before treatment (P>0.05). These results suggest that 1) there is an abnormal increase in intestinal motility indicating an intestinal motility disorder in IBS rats; 2) EA but not sham EA can relieve such intestinal motility disorder.