比较电针“合谷”“足三里”穴对IBS模型大鼠结肠动力及结肠M_3受体表达的影响

Comparing the colonic motility and expression of M_3 muscarinic receptor in IBS rats by stimulating LI4 and ST 36 with electroacupuncture

目的观察并比较电针"合谷""足三里"穴对肠易激综合征(IBS)模型大鼠结肠动力及结肠M_3受体免疫反应物阳性表达的影响,初步探讨电针不同穴性及不同神经节段支配的穴位对IBS的效应差异及结肠动力改变的相关机制。方法选取新生wistar大鼠40只,随机分为空白对照组、模型对照组、合谷组和足三里组。除空白对照组外,均采用新生期母婴分离、醋酸灌肠及结直肠扩张刺激(CRD)的方法联合制备IBS大鼠模型。大鼠9周龄时,合谷组和足三里组分别给予电针(EA)干预,隔日1次,共5次。空白对照组及模型对照组不予干预。治疗结束后,按照Bristol大便分类法观察电针前后IBS大鼠的便型,采用腹部回撤反射(AWR)对大鼠进行肠道敏感性及平滑肌收缩强度评估,观察潜伏期、收缩波个数、起始波压力值;采用免疫组织化学法检测结肠M_3受体的表达。结果与针前相比,针后合谷组及足三里组大鼠的大便评分显著降低(P<0.01)。与空白对照组相比,模型对照组大鼠的大便评分显著增高(P<0.01),潜伏期明显缩短(P<0.01),收缩波个数明显增多(P<0.01),起始波压力值明显降低(P<0.01),结肠内M_3受体免疫反应物阳性表达水平明显增强(P<0.01);合谷组结肠内M_3受体免疫反应物阳性表达水平增强(P<0.05)。与模型对照组相比,合谷组和足三里组大鼠针后的大便评分均显著降低(P<0.01),潜伏期均明显延长(P<0.01),合谷组和足三里组收缩波个数明显减少(P<0.01,P<0.05),起始波压力值均明显增高(P<0.01),结肠内M_3受体免疫反应物阳性表达水平明显下降(P<0.01)。与合谷组相比,足三里组大鼠的大便评分降低(P<0.05),起始波压力值显著降低(P<0.01),结肠内M_3受体免疫反应物阳性表达水平下降(P<0.05)。结论电针"合谷""足三里"穴均可抑制IBS模型大鼠肠道收缩,改善肠道敏感性,缓解IBS症状。但"合谷"穴缓解腹痛效果更佳,而"足三里"穴减轻腹泻作用更强。说明电针不同穴性及不同神经节段支配的穴位对IBS疗效具有经穴效应特异性。

Objective To observe and compare the effects of LI 4 and ST 36 electroacupuncture on colonic motility and positive expression of M_3 receptor in colon of irritable bowel syndrome（ IBS） model rats,and to explore the mechanism behind those differences. Methods 40 neonatal Wistar rats were randomly divided into blank control group,model group,LI 4 group,and ST 36 group. IBS rat model was built by using neonatal maternal separation and acetic acid enema,and colorectal distension（ CRD）stimulation in rats except the blank control group. At 9 weeks rats in LI 4 group and ST 36 group were given electroacupuncture（ EA） intervention once every other day for 5 times. Blank group and model group didn＇t receive acupuncture intervention. After the treatment,Bristol Stool Scale was applied to identify the feces types of the IBS rats before and after electroacupuncture invention; Abdominal withdrawal reflex（ AWR） was evaluated to asess the intestinal sensitivities and smooth muscle contraction intensity; and latency,contraction wave and pressure value of initial wave were observed; The expression of M_3 receptor was measured using immunohistochemistry. Results Bristol scores of LI 4 group and ST 36 group significantly decreased（ P〈0. 01）. Compared with blank group,the stool score of model group was significantly increased（ P〈0. 01）; the latency was shortened（ P〈0. 01）; the number of contraction waves was significantly increased（ P〈0. 01）; the immunohistochemical expression of M_3 receptor in the colon was significantly increased（ P〈0. 01）. The immunohistochemical expression of M_3 receptor in the colon in LI 4 group was increased（ P〈0. 01）. Compared with model group,after electroacupuncture stimulation,the stool score of LI 4 group and ST 36 group was significantly decreased（ P〈0. 01）; the latency was significantly prolonged（ P〈0. 01）; the number of contraction wave was significantly decreased in LI 4 group（ P〈0. 01） and ST 36 group（ P〈0. 05）; immunohistochemical expression of M_3 receptor in the colon was significantly decreased（ P〈0. 01）. Compared with the LI 4 group,the stool score in ST 36 group was decreased（ P〈0. 05）; the pressure value of initial wave significantly decreased（ P〈0. 01）; the immunohistochemical expression of M_3 receptor in the colon was decreased（ P〈0. 05）. Conclusion Stimulating LI 4 or ST 36 with electroacupuncturing could both inhibit gastrointestinal tract contraction,reduce intestinal sensitivity and relieve IBS symptoms in rats. LI 4 appears to be more effective than ST 36 in relieving abdominal pain,while ST 36 is better than LI 4 to stop diarrhea.Stimulating different acupoints or acupoints on different nerve segments with electro-acupuncture have specific effects on IBS rats.