Electroacupuncture at Tianshu (ST 25) for diarrhea-predominant irritable bowel syndrome using positron emission tomography Changes in visceral sensation center

Previous studies have demonstrated that electroacupuncture therapy is effective in the treatment of irritable bowel syndrome. However, the precise mechanism of this therapy is unknown. The present study served to investigate the effects of electroacupuncture therapy on treatment of patients with diarrhea-predominant irritable bowel syndrome （IBS）. We compared brain activation maps based on the changes of cerebral glucose metabolism obtained by 18-fluorodeoxyglucose positron emission tomography scanning under three conditions： resting, rectal balloon distension and rectal balloon distension plus electroacupuncture. Under the resting condition, compared with healthy controls, IBS patients displayed an increasing regional cerebral metabolic rate of glucose over a wide range： bilateral superior temporal gyrus, right middle occipital gyrus, superior frontal gyrus and bilateral middle frontal gyrus. However, there was no significant activity in the visceral pain center. Compared with the resting condition, under the rectal balloon distension condition, patients with IBS had a greater regional cerebral metabolic rate of glucose in the prefrontal cortex, left anterior cingulate cortex, postcentral gyrus, precentral gyrus and temporal gyrus. Under the rectal balloon distension plus electroacupuncture condition, stimulation by electroacupuncture at Tianshu （ST 25） manifested a decreased regional cerebral metabolic rate of glucose in the left cingulate gyrus, right insula, right caudate nucleus, fusiform gyrus and hippocampal gyrus. Electroacupuncture therapy relieved abdominal pain, distension or discomfort by decreasing glucose metabolism in the brain.

Effects of electroacupuncture on c-Fos expression in the spinal cord and brain of rats with chronic visceral hypersensitivity

BACKGROUND： Visceral hypersensitivity is the main cause of irritable bowel syndrome, c-Fos is a marker of visceral hypersensitivity in the central nervous system. Electroacupuncture can relieve chronic visceral hypersensitivity in rats, but the mechanism is still unknown. OBJECTIVE： To identify c-Fos expression in the spinal cord and cerebral cortex of rats with chronic visceral hypersensitivity, and to test the effects of electroacupuncture on pain sensitivity in rats with chronic visceral hypersensitivity. DESIGN, TIME AND SETTING： A randomized controlled animal experiment was performed at the Animal E：~perimental Center, Shanghai University of Traditional Chinese Medicine, from January to April, 2007. MATERIALS： A total of 24 neonatal, male, Sprague Dawley rats, aged five days old, were equally and randomly assigned into a normal group, a model group, and an electroacupuncture group. Rabbit anti-rat c-Fos antibody and Evision secondary antibody kits （Sigma, USA）, diaminobenzidine kit （Dako, Denmark）, and an LD202H electroacupuncture apparatus （Huawei, Beijing, China） were used in this study. METHODS： Neonatal rats from the model and electroacupuncture groups were used to establish rat models of chronic visceral hypersensitivity by the saccule stimulation method. After model establishment, 0.25 mm diameter electric needles were inserted into Tianshu （ST 25） and Shangjuxu （ST37） at a depth of approximately 0.5 cm, with an square wave （alternating current frequency at 100/20 Hz, amplitude ranged 0.2-0.6 ms, intensity at 1 mA） once for 20 minutes, once a day, for seven days. Rats in the normal and model groups were not treated. MAIN OUTCOME MEASURES： Following 7 days of treatment, c-Fos expression in the spinal cord and cerebral cortex was detected by immunohistochemistry. After the first electroacupuncture treatment, abdominal withdrawal reflex scores were investigated to evaluate the pain threshold for chronic visceral hypersensitivity in rats. RESULTS： Visceral hypersensitivity increased c-Fos staining （P 〈 0.05）, and electroacupuncture significantly decreased the number of these cells to near normal levels （P 〉 0.05）. Abdominal withdrawal reflex scores were significantly lower in the electroacupuncture and normal groups than in the model group （P 〈 0.05） and were similar between the electroacupuncture and normal groups （P 〉 0.05）. CONCLUSION： Electroacupuncture decreases c-Fos expression in the spinal cord and cerebral cortex and increases pain threshold in a chronic visceral hypersensitivity model in rats.