Study on Improvement of Visceral Hypersensitivity in Rats with Chronic Stress-Induced IBS Induced through Regulation of NOS Neurons by EA
Objective:To observe the effects of electro-needling Tianshu(ST25),Zusanli(ST36)and Dachangshu(BL25)on the number of fecal granules,visceral pain sensitivity and nitric oxide synthase(NOS)positive neurons in colonic tissues of model rats with chronic stress-induced irritable bowel syndrome(IBS),and to investigate the possible mechanism of EA intervention on IBS.Methods:70 male Wistar rats were randomly divided into the normal group,the model group,the ST25 group,the ST36 group and the BL25 group,with 14 rats in each group.The IBS model was established by using a combination of water avoidance stress(WAS)method and chronic unpredictable mild stress(CUMS)method.The intervention groups were treated with electro-needling ST25,ST36 and BL25 respectively.The abdominal withdrawal reflex(AWR)and electromyography(EMG)were used to assess the sensitivity of the internal organs,the electrical signals of the colon were collected,and the NOS positive neurons in the colon were detected by immunohistochemistry and Western Blot methods.Results:Compared with those in the normal group,the number of fecal pellets were increased and then decreased(P＜0.05),the AWR score was increased(P＜0.01),the frequency of colon slow wave rhythm was signifiicantly decreased(P＜0.01),and the spikes of rectus abdominal EMG,the number of NOS positive neurons and the NOS protein expression were increased in the model group(P＜0.05).EA treatment could reverse the above changes,and the AWR score was lower in the ST25 group than that in the BL25 group and the ST26 group(P＜0.05).Conclusion:Electro-needling ST25,ST36 and BL25 can alleviate the symptoms of IBS through down-regulating NOS positive neurons in myenteric plexus of colons,reducing visceral sensitivity and restoring colonic motility.Electro-needling ST25 had a more pronounced effect on the regulation of visceral sensitivity than electro-needling ST36 and BL25.
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