电针预处理对内脏痛大鼠脊髓背角 p38 和 c-Fos 表达的影响。

Effect of pre-electroacupuncture on p38 and c-Fos expression in the spinal dorsal horn of rats suffering from visceral pain.

机构信息

Department of Digestive Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.

出版信息

Chin Med J (Engl). 2010 May 5;123(9):1176-81.

PMID:20529559

Abstract

BACKGROUND

Acupuncture is an effective way to relieve pain, but the mechanism by which electroacupuncture (EA) decreases the visceral pain state still remains unclear. This study aimed to evaluate the effects of pre-electroacupuncture on pain behaviors, p38 phosphorylation, and c-Fos protein and mRNA expression in both the colonic wall and spinal dorsal horn of rats suffering from visceral pain. This study also investigated the probable signaling regulatory mechanism of the analgesic effect induced by electroacupuncture.

METHODS

All rats were randomized into the control (Con) group, the Con + EA group, the visceral pain (VP) group, and VP + EA group (n = 8 for all groups). The visceral pain model was established using 40 microl of 5% formalin solution injected into the colon of rats. EA was applied to the bilateral Jiaji acupoints for 20 minutes before application of visceral pain. Parameters for EA were set at a continuous wave (20 Hz) and intensity where the rats shook their whiskers but did not scrabble (< or = 1 mA). The visceral pain score was recorded and the expressions of p38 and c-Fos protein were detected using Western blotting. Real-time quantitative PCR was also used to determine the expression of c-Fos mRNA.

RESULTS

Rats in the VP group immediately presented with obvious visceral pain behaviors after being injected with formalin. p38 activity and c-Fos protein and mRNA expression in both the colonic wall and spinal dorsal horn were higher in the VP group than in the Con group (P < 0.05). By contrast, visceral pain behaviors were delayed in rats from the VP + EA group. p38 activity and c-Fos protein and mRNA expression were lower in the VP + EA group than that in the VP group (P < 0.01).

CONCLUSIONS

Pre-electroacupuncture of the Jiaji acupoint has prophylactic analgesic effects on rats suffering from visceral pain. The p38 signal transduction pathway may be partly involved in the regulatory mechanism of this analgesic effect.

摘要

背景

针刺是缓解疼痛的有效方法，但电针（EA）降低内脏痛状态的机制尚不清楚。本研究旨在评估电针预处理对内脏痛大鼠结肠壁和脊髓背角疼痛行为、p38 磷酸化、c-Fos 蛋白和 mRNA 表达的影响，探讨电针镇痛效应的可能信号调节机制。

方法

所有大鼠随机分为对照组（Con）、Con+EA 组、内脏痛（VP）组和 VP+EA 组（每组 8 只）。采用 40μl 5%福尔马林溶液注入大鼠结肠建立内脏痛模型。在应用内脏痛前，对双侧夹脊穴进行 20 分钟的电针刺激。电针参数设定为连续波（20Hz），强度为大鼠抖动胡须但不搔抓（≤1mA）。记录内脏痛评分，采用 Western blot 检测 p38 和 c-Fos 蛋白表达，实时定量 PCR 检测 c-Fos mRNA 表达。

结果

VP 组大鼠在注射福尔马林后立即出现明显的内脏痛行为。VP 组大鼠结肠壁和脊髓背角 p38 活性及 c-Fos 蛋白和 mRNA 表达均高于 Con 组（P<0.05）。而 VP+EA 组大鼠的内脏痛行为延迟。VP+EA 组大鼠结肠壁和脊髓背角 p38 活性及 c-Fos 蛋白和 mRNA 表达均低于 VP 组（P<0.01）。