Electroacupuncture at Zusanli (ST36) ameliorates colonic neuronal nitric oxide synthase upregulation in rats with neurogenic bowel dysfunction following spinal cord injury

Abstract

Study designExperimental study.ObjectiveTo determine the effects of electroacupuncture (EA) at Zusanli (ST36) on colonic motility and neuronal nitric oxide synthase (nNOS) expression in rats with neurogenic bowel dysfunction (NBD) after spinal cord injury (SCI).SettingSecond School of Clinical Medical, Nanjing University of Chinese Medicine, Jiangsu, China.MethodsWe divided 30 adult Sprague-Dawley rats into a sham group (10 rats), a model group (SCI alone, 10 rats) and a EA group (SCI+EA at ST36, 10 rats). Defecation time was recorded as the time from activated carbon administration (on day 15) to evacuation of the first black stool. Immunohistochemical, real-time PCR and western blot analyses were performed to assess changes in nNOS-immunoreactive cells, and nNOS messenger RNA (mRNA) and protein, respectively, after 14 experimental days.ResultsDefecation time was lower in the EA group than in the model group (P<0.01). On immunohistochemical analysis, nNOS was localized in the myenteric plexus of the colon. The number of nNOS-immunoreactive cells and the intensity of nNOS staining were greater in the model group than in the sham group and lesser in the EA group than in the model group. Consistent with the immunohistochemical findings, nNOS mRNA and protein expression was higher in the model group than in the sham group and lower in the EA group than in the model group (P<0.05 for both).ConclusionIncreased colonic nNOS expression can induce/aggravate NBD in SCI rats. EA at ST36 ameliorated NBD, possibly by downregulating colonic nNOS expression.