电针刺“环跳”穴对大鼠癌性疼痛及瞬时受体电位香草酸亚型1 mRNA表达的影响

Effects of electroacupuncture at Huantiao on cancer pain and transient receptor potential vanilloid subfamily 1 expression in rats

目的探讨电针刺"环跳"穴对由肿瘤细胞种植所引起的大鼠癌性疼痛的作用及背根神经节瞬时受体电位香草酸亚型1 mRNA表达的影响,研究电针镇痛的神经机制。方法 Wistar大鼠随机分为4组:正常对照组(NC),肿瘤对照组(TC),电针刺激组(EA)和假电针刺激组(SEA),每组8只。将100μL含有106个Walker 256细胞的溶液注入到大鼠右侧脚掌趾部建立癌痛模型。移植后2～10天,每天电针刺激30 min。通过大鼠静息状态下自发动作观察自发非刺激性疼痛反应,大鼠机械性刺激及热刺激痛阈分别利用von Frey和热板实验评估。TRPV1 mRNA水平通过实时定量PCR测定。结果 Walker 256肿瘤细胞接种能引起明显的癌性疼痛(P<0.05),电针刺"环跳"穴能减轻癌性疼痛(P<0.05)。肿瘤细胞接种后,背根神经节TRPV1 mRNA表达增高(P<0.05),针刺后其表达无明显变化(P>0.05)。结论电针刺"环跳"穴能减轻由Walker 256肿瘤细胞接种大鼠右侧脚掌趾部所引起癌性疼痛,但镇痛机制与背根神经节TRPV1 mRNA表达无明显关系。

Objective To evaluate the effect of electroacupuncture （EA） on cancer pain caused by intraplantar injection of Walker 256 carcinoma cells and cancer-driven transient re- eeptd potential vanilloid subfamily 1 （ TRPV1 ） mRNA expression in the dorsal root ganglions （DRGs）. Methods Rats were randomly divided into four groups （n = 8, each group） ： Non- tumor cell inoculation group （NC）; Walker 256 carcinoma cells inoculation group （TC）; Sham acupoint EA treatment group （SEA）; EA treatment group （EA）. Mechanical pain thresholds and thermal hyperalgesia latency were determined by von Fray and hot plate test. TRPV1 mRNA in DRGs was observed by quantitative real-time polymerase chain reaction （RT- PCR）. Results Injection of Walker 256 cancer cells induced cancer pain, and EA at ＂ Huan- tiao＂ aeupoint attenuated this kind of pain （P 〈 0.05）. TRPV1 mRNA increased in cancer pain model （P 〈 0. 05 ） , but EA at ＂ Huantiao＂ acupoint did not counteract the cancer-driven upregulation of TRPV1 expression in the corresponding DRGs （P 〉 0.05）. Conclusion EA at ＂ Huan-tiao＂ acupoint could attenuate cancer pain induced by the inoculation of Walker 256 cells, but the mechanism of this effect may not be due to the suppression of EA on TRPV1 mRNA in the DRGs.