电针通过调控NOS神经元改善慢性应激致肠易激综合征大鼠的内脏痛敏的研究

Study on Improvement of Visceral Hypersensitivity in Rats with Chronic Stress-Induced IBS Induced through Regulation of NOS Neurons by EA

目的:观察电针“天枢”“足三里”“大肠俞”对慢性应激致肠易激综合征(IBS)模型大鼠粪便粒数、内脏痛敏及结肠-氧化氮合酶阳性(NOS)神经元表达的影响,探讨电针干预IBS的机制。方法:70只大鼠随机分为正常组、模型组、天枢组、足三里组和大肠俞组,每组14只。模型组、天枢组、足三里组和大肠俞组采用慢性避水应激(WAS)方法和慢性不可预测轻度应激(CUMS)法联合建立动物模型。天枢组、足三里组、大肠俞组分别电针大鼠双侧“天枢”“足三里”“大肠俞”穴。采用腹壁回撤反射(AWR)、腹直肌肌电(EMG)评估大鼠内脏敏感性,采集结肠电信号,免疫组化法、Western blot法检测结肠NOS阳性神经元表达。结果:造模后,与正常组比较,模型组大鼠粪便颗粒数先增多后减少,差异有统计学意义(P<0.05),AWR评分升高,差异有统计学意义(P<0.01),结肠慢波频率减慢,差异有统计学意义(P<0.01),腹直肌放电、结肠NOS阳性神经元和NOS蛋白表达均增多,差异有统计学意义(P<0.05)。电针治疗均可逆转上述变化,且天枢组AWR评分低于大肠俞组、足三里组,差异有统计学意义(P<0.05)。结论:电针“天枢”“足三里”“大肠俞”可通过下调结肠肌间神经网NOS阳性神经元的表达,减轻其内脏敏感性,从而恢复结肠运动,缓解肠易激症状;电针“天枢”穴对内脏敏感性的调节作用较“足三里”“大肠俞”穴更为明显。

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 significantly 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.