辣椒素处理对电针“四白”穴诱导三叉神经脊束核尾侧亚核c-fos表达的影响

Effect of Capsaicin-pretreatment on "Sibai"(ST 2)-electroacupuncture Induced Changes of c-fos Expression in Rat Caudal Spinal Trigeminal Nucleus

目的:探讨四白穴针刺效应的传入途径。方法:SD大鼠36只,随机分成空白组、假手术组、辣椒素组、溶媒组、电针"四白"穴+辣椒素组、电针"四白"穴+溶媒组。游离一侧眶下神经,辣椒素组将浸泡有1.5%辣椒素的棉条包绕在眶下神经上。溶媒组用浸泡在溶媒中的棉条包绕在眶下神经上。采用免疫组化技术观察三叉神经脊束核尾侧亚核(cSTN)的c-fos表达。结果:空白组在cSTN各层可见到零星、散在的阳性细胞。溶媒组、辣椒素组以及假手术组cSTN的c-fos阳性细胞数与空白组相似。电针"四白"穴+溶媒组c-fos在cSTN内主要集中在浅层(Ⅰ-Ⅱ层),其阳性细胞的数量明显多于其余各组(P<0.01);cSTN的深层(Ⅲ-Ⅳ层)c-fos数量多于空白组、溶媒组和假手术组(P<0.01,P<0.05,P<0.05)。电针"四白"穴+辣椒素组cSTN的Ⅰ-Ⅱ板层的c-fos阳性细胞数与电针"四白"穴+溶媒组相比明显减少(P<0.01),但cSTN的Ⅲ-Ⅳ板层的c-fos阳性细胞数与电针"四白"穴+溶媒组相比无明显变化(P>0.05)。结论:C纤维可能是四白穴针刺效应(调节胃功能活动)的主要传入途径。

Objective To explore the afferent pathway of signals from electroacupuncture （EA） at ＂Sibai＂ （ST 2） acupoint. Methods A total of 36 SD rats were randomly divided into control, sham operation （sham）, capsaicin, vehicle, capsaicin＋ EA, and vehicle＋ EA groups, with 6 cases in each. EA （ 1/20 Hz, 1 - 3 mA） was applied to ＂Sibai＂ （ST 2）. After anesthesia （10% urethane）, unilateral infraorbital nerve was separated to be immersed in a 1.5% capsaicin-fluid-soaked cotton ball for lesion of C fibers. Vehicle （20% tween） was used to immerse infraorbital nerve for vehicle and vechile＋ EA groups. The expression of c-fos in the caudal spinal trigeminal nucleus （cSTN） was detected by immunohistochemistry. Results In control group, c-fos immune-reaction （IR） positive neurons were observed to scatter in every layer of cSTN. No significant differences were found among vehicle, capsaicin, sham and control groups in the number of c-los IR positive neurons in cSTN. The number of c-fos positive neurons in .the Ⅰ- Ⅱ layers of cSTN was obviously increased following EA at ST2, being significant more than that in control, vehicle, capsaicin and sham groups （P〈0. 01 respectively）. However, the number of c-fos IR-positive neurons in Ⅲ- Ⅳ layers of cSTN haci no marked change. In capsaicin＋ EA group, the number of c-fos-IR positive neurons in the Ⅰ - Ⅱlayers of cSTN was obviously less than that in vehicle and vehicle ＋ EA groups （ P〈0. 01 ）, but no significant changes were found in Ⅲ - Ⅳ layers of cSTN. Conclusion C afferent fibers of the infraorbital nerve are the primary afferent pathway of EA signals from Sibai （ST 2） stimulation in the rat.