电针对慢性内脏痛敏大鼠延髓头端腹内侧核NMDA-R1受体表达的影响

目的在电针（EA）缓解肠易激综合征（IBS）模型大鼠慢性内脏痛敏基础上,观察电针处理对IBS模型大鼠延髓头端腹内侧核（RVM）N-甲基-D-门冬氨酸1型（NMDA-R1）受体表达的影响。方法将新生9 d SD幼鼠分为两组,第一组通过结直肠机械扩张刺激制作IBS慢性内脏痛敏模型,持续两星期;另一组仅轻柔肛周皮肤作为对照。饲养至6～8星期后,分别观察两组大鼠由结直肠扩张（CRD）诱发的腹部撤回反射（AWR）评分和痛阈压力值（PTP）变化。继而随机将IBS模型大鼠分为模型组（M）、模型加电针组（EA）和模型加假电针组（SEA）。模型组不做任何治疗,电针组穴位取双侧＂足三里＂和＂上巨虚＂,连续隔日治疗4次,假电针不通电,余与电针组同。治疗结束后,取材并用免疫组化方法观察各组大鼠RVM中NMDA-R1受体表达变化。结果成年IBS大鼠AWR评分明显升高（P〈0.01）,PTP值明显降低（P〈0.01）;电针可以明显降低AWR评分（P〈0.05）,并使PTP值明显升高（P〈0.01）;假电针则没有此作用。IBS大鼠RVM中NMDA-R1受体阳性神经元数目和积分光密度明显高于正常对照大鼠（P〈0.05）;而电针可使其表达明显降低（P〈0.05）;假电针则没有这样的作用。结论电针对IBS大鼠的慢性内脏痛敏具有良好的治疗作用,其作用机制可能通过调节脑内RVM中NMDA-R1受体表达来发挥的。

Effect of Electroacupuncture on Expression of NMDA-R1 Receptor in the Rostral Ventromedia Medulla of Rats with Chronic Visceral Hyperalgesia

Objective To investigate the effect of electroacupuncture（EA） on the expression of N-methyl-D-aspartate receptor 1（NMDA-R1） in the rostral ventromedia medulla（RVM） on the basis of EA relieving chronic visceral hyperalgesia in a rat model of irritable bowel syndrome（IBS）.Methods Nine-day-old SD rats were allocated to two groups.In one group,a model of IBS chronic visceral hyperalgesia was made by 2 weeks＇ mechanical dilation of colorectum.In the other group as a control,perianal skin was kneaded lightly.Colorectal distention（CRD）-induced abdominal withdraw reflex（AWR） was scored and pain threshold pressure（PTP） was measured in the two groups at 6-8 weeks after feeding.Then,IBS rats were randomly allocated to model,electroacupuncture and sham electroacupuncture groups.The model group was not given treatment.In the electroacupuncture group,bilateral points Zusanli and Shangjuxu were selected and treatment was given once every other day for 4 times.The sham electroacupuncture group was given the same treatment as in the electroacupuncture group except no electrification.After treatment was finished,the specimen was taken and the expression of NMDA-R1 in RVM was examined by an immunohistochemical method in each group of rats.Results The AWR score increased significantly（P0.01） and PTP decreased significantly（P0.01） in the adult IBS rats.Electroacupuncture increased the AWR score significantly（P0.05） and decreased PTP significantly（P0.01）.Sham electroacupuncture had no such effects.The number and integrated optical density of RVM NMDA-R1-positive neurons were significantly higher in the IBS rats than in the normal control rats（P0.05）.Electroacupuncture increased its expression significantly（P0.05）.Sham electroacupuncture had no such effect.Conclusions Electroacupuncture has a good therapeutic effect on chronic visceral hyperalgesia in IBS rats.The mechanism of its action may be that it regulates the expression of NMDA-R1 in RVM.