Piezo2介导针刺得气客观反应及镇痛效应的机制研究

Study on the Mechanism of Piezo2-mediated Objective Deqi Response and Analgesic Effect of Acupuncture

关键词:  针刺  得气  镇痛  肌电  Piezo2

Key words:  acupuncture  Deqi  analgesia  EMG  Piezo2

摘要:

[目的] 构建针刺实验动物得气客观反应研究平台，探讨穴区Piezo2通道是否介导了针刺得气客观反应及镇痛效应。[方法] 实验1，将SD大鼠随机分为模型组、不行手法组、行手法组，采用右侧足底皮下注射0.1 mL完全弗氏佐剂（CFA）进行造模。行手法组于大鼠“足三里”穴刺入3~5 mm，以180次/min行捻转法刺激2 min，间隔5 min后再次行针，共4次，每日1次，共3 d，不行手法组刺入同样深度，仅留针30 min。检测针刺时穴区局部肌电反应和出针时毫针牵拉力，以此作为得气客观反应指标；检测足底热痛缩足反应潜伏期（PWL）评价疼痛效应，采用免疫荧光染色法检测大鼠L4背根神经节（DRG）中Piezo2阳性神经元的激活情况。实验2，大鼠随机分为模型+对照液组、模型+Piezo2抑制剂组、行手法+对照液组和行手法+Piezo2抑制剂组，每组6只，针刺前20 min于“足三里”穴区肌肉注射对照液（纯水）或抑制剂20 μL，行手法操作及检测指标同实验一。[结果] 针刺行手法相对不行手法可以显著提高佐剂性关节炎（AIA）模型大鼠右足底热辐射痛阈，诱发穴区肌电发放并使毫针牵拉力升高，能显著激活L4 DRG中Piezo2表达神经元；穴区注射Piezo2通道抑制剂再行针刺，L4 DRG中Piezo2阳性神经元激活比例下降，穴区肌电发放减弱，毫针牵拉力降低，针刺镇痛效应被阻断。[结论] 针刺行手法可诱发CFA大鼠得气客观反应并产生镇痛效应，Piezo2介导了针刺得气客观反应和镇痛效应的产生，是针刺效应穴区启动的关键通路之一。

Abstract:

[Objective] To make the construction of a research platform for the objective Deqi response in acupuncture experimental animals and to conduct the exploration of whether the Piezo2 channel in the acupoint area mediates the objective Deqi response and analgesic effect of acupuncture.[Methods] In Experiment 1, the random division of SD rats into a model group, a non-manipulation group, and a manipulation group was conducted. The establishment of the model by the subcutaneous injection of 0.1 mL Complete Freund's Adjuvant(CFA) into the right plantar was conducted. In the manipulation group, the “Zusanli”(ST36) acupoint of the rat was inserted 3~5 mm deep, stimulated by rotating manipulation at 180 times/min for 2 minutes, with a 5-minute interval before the next needle manipulation, repeated 4 times, once daily for 3 days. The non-manipulation group was inserted to the same depth but retained for 30 minutes without manipulation. The measurement of the local electromyographic(EMG) response during acupuncture and the pulling force of the needle upon withdrawal as objective indicators of Deqi was conducted;the paw withdrawal latency(PWL) to thermal pain was measured fir the evaluation of the pain effect;and the activation of Piezo2-positive neurons in the L4 dorsal root ganglion(DRG) was detected by immunofluorescence staining. In Experiment 2, the random division of rats into model+control liquid group, model+Piezo2 inhibitor group, manipulation+control liquid group, and manipulation+Piezo2 inhibitor group was conducted, with 6 rats in each group. 20 minutes before acupuncture, 20 μL of control liquid(pure water) or inhibitor was injected into the muscle of the “Zusanli” acupoint area. The manipulation and measurement indicators were the same as in Experiment 1.[Results] In contrast with non-manipulation, the thermal radiation pain threshold of the right plantar in AIA model rats could be significantly increased by acupuncture manipulation, EMG discharges in the acupoint area could be induced, and the pulling force of the needle could be increased, with Piezo2-expressing neurons in the L4 DRG being significantly activated. When the Piezo2 channel inhibitor was injected into the acupoint area before acupuncture, the activation ratio of Piezo2-positive neurons in the L4 DRG was decreased, the EMG discharges in the acupoint area were weakened, the pulling force of the needle was reduced, and the analgesic effect of acupuncture was blocked.[Conclusion] The objective Deqi response can be induced and an analgesic effect can be produced in CFA rats through acupuncture manipulation. Piezo2 is mediated in the generation of the objective Deqi response and analgesic effect, and is one of the key pathways for the initiation of the acupuncture effect in the acupoint area.