基于“合治内腑”理论研究针刺上巨虚对IBS内脏痛敏模型大鼠室旁核NGF-TrkA通路的影响

Our group foud in clinic that acupuncture can alleviate the visceral pain in irritable bowel syndrome (IBS), and in experiment we aslo foud paraventricular nucleus participate in the effect of alleviating the visceral pain by acupuncture Shangjuxu acupoint, but the mechanism is not yet clear. Recent researches foud that acupuncture and moxibustion can alleviate the visceral pain in IBS by adjust the TRPV1 expression. And some studies have shown that NGF-TrkA signaling pathway participate in IBS with visceral pain sensitivity by mediating TRPV1 expression. This study intend to develop the model rats with chronic visceral pain sensitivity by colorectal distension on newly born rats, then observe the acupuncture effect of Shangjuxu (low He point of large intestine fu) for IBS with visceral pain sensitivity based on the theory of “curing viscera diseases by He points”, and use immunohistochemistry, Western blot and RT-PCR technique to test the protein and mRNA expression of NGF, TrkA, PLC-γ, TRPV1 in colon and paraventricular nucleus. Then analysis the effect of acupuncture Shangjuxu for treating IBS whether through NGF-TrkA signaling pathway by mediated TRPV1 expression in paraventricular nucleus, so as to provide experimental basis for the clinical application of acupuncture in the treatment of IBS.

课题组在临床发现针刺能较好的改善肠易激综合征（IBS）患者反复发作的腹痛，且前期实验研究发现室旁核参与针刺上巨虚缓解结直肠扩张刺激所致内脏痛的中枢调节，但其具体作用途径尚未清楚。最近研究发现针灸可通过调节瞬时受体电位香草酸受体 1（TRPV1）的表达，达到缓解IBS内脏痛敏的作用。而研究显示NGF-TrkA信号通路可通过调节 TRPV1的表达参与介导IBS内脏痛敏的发生。本研究拟以结直肠扩张刺激制备大鼠IBS慢性内脏痛敏模型，依据“合治内腑”理论选用大肠下合穴上巨虚，观察针刺其对IBS内脏痛敏的作用，并用免疫组化、Western blot和RT-PCR检测大鼠结肠与室旁核NGF、TrkA、PLC-γ、TRPV1蛋白和基因的表达，分析针刺上巨虚是否通过室旁核NGF-TrkA信号通路调节 TRPV1的表达从而达到治疗IBS的作用，为针灸治疗IBS的临床应用提供实验依据。

研究表明NGF-TrkA及其下游PI3K信号通路可能参与介导IBS内脏痛敏的发生，针刺治疗IBS内脏痛敏的取效途径是否通过该通路是本项目的研究目标。本研究以结直肠扩张制备大鼠IBS慢性内脏痛敏模型，通过检测反映大鼠内脏痛的AWR评分，发现针刺上巨虚有降低AWR评分改善大鼠内脏痛的作用，用免疫组化、Western blot与qPCR技术检测大鼠结肠NGF、TrkA、PI3K、TRPV1蛋白与mRNA的表达，发现针刺上巨虚可以下调大鼠结肠NGF、TrkA、PI3K、TRPV1蛋白与mRNA的表达，与模型组比差异有统计学意义，并且针刺上巨虚优于非穴。而针刺上巨虚降低AWR评分与下调TRPV1的作用可以被PI3K信号通路阻断剂LY294002所逆转，这表明针刺上巨虚缓解IBS内脏痛敏的作用机理，可能与NGF-TrkA介导的PI3K信号通路通过调节 TRPV1的表达从而参与调控IBS内脏痛敏密切相关，为临床针灸治疗IBS提供了实验依据。