Zhang Rong Yi, Zhu Ben Fan, Wang Li Kui, Song Yang, Zhao Jia Gui, Guo Yan, Zhao Long, Chen Shi
Anhui Medical University, The First Affiliated Hospital, Department of Pain Management, Hefei, Anhui Province, China.
Arq Neuropsiquiatr. 2020 Oct;78(10):617-623. doi: 10.1590/0004-282X20200078.
Acupuncture has been widely used for alleviating pain. However, its mechanisms remain largely enigmatic.
In the present study, we focused on whether the analgesic effect of electroacupuncture is related to its regulation on adenosine and substance P expression.
We established chronic inflammatory pain model in rats through a single injection of Complete Freund's Adjuvant, and then we treated animals using daily electroacupuncture. We applied seven bilateral sessions of electroacupuncture (ST36 and BL60, 0.5 to 1.5 mA, initial strength of 0.5 mA, increased by 0.5 mA every 10 minutes, for 30 minutes per session, one section per day) to Complete Freund's Adjuvant rats for seven days. The analgesic effect of electroacupuncture was evaluated by measuring paw withdrawal threshold in rats that received mechanical and thermal stimulation.
Daily electroacupuncture stimulation effectively increased paw withdrawal threshold in Complete Freund's Adjuvant rats. Electroacupuncture increased the adenosine level in zusanli. A further study showed that electroacupuncture could decrease substance P, neurokinin-1 receptor, tumor necrosis factor-alpha, interleukin-1β, interleukin-6 and CD68 levels in dorsal root ganglion. Interestingly, direct injection of adenosine A1 or substance P receptor antagonists, or dorsal nerve root transection could significantly impair electroacupuncture induced analgesic actions in Complete Freund's Adjuvant rats could and reduce the levels of substance P, neurokinin-1 receptor, tumor necrosis factor-alpha, interleukin-1β, interleukin-6 and CD68. Finally, we confirmed that direct injection of adenosine A1 receptor agonist replicated the analgesic effect of electroacupuncture.
Our results indicate regulation of adenosine-mediated substance P secretion. Substance P-mediated pathway may be involved in the analgesia process by electroacupuncture in rats.
针刺已被广泛用于缓解疼痛。然而，其机制在很大程度上仍然是个谜。
在本研究中，我们聚焦于电针的镇痛作用是否与其对腺苷和P物质表达的调节有关。
通过单次注射完全弗氏佐剂在大鼠中建立慢性炎性疼痛模型，然后每日对动物进行电针治疗。我们对完全弗氏佐剂大鼠进行七次双侧电针治疗（足三里和膀胱经60穴，0.5至1.5毫安，初始强度0.5毫安，每10分钟增加0.5毫安，每次治疗30分钟，每天一次），持续七天。通过测量接受机械和热刺激的大鼠的爪退缩阈值来评估电针的镇痛效果。
每日电针刺激有效提高了完全弗氏佐剂大鼠的爪退缩阈值。电针增加了足三里中的腺苷水平。进一步的研究表明，电针可降低背根神经节中P物质、神经激肽-1受体、肿瘤坏死因子-α、白细胞介素-1β、白细胞介素-6和CD68的水平。有趣的是，直接注射腺苷A1或P物质受体拮抗剂，或切断背神经根可显著削弱完全弗氏佐剂大鼠中电针诱导的镇痛作用，并降低P物质、神经激肽-1受体、肿瘤坏死因子-α、白细胞介素-1β、白细胞介素-6和CD68的水平。最后，我们证实直接注射腺苷A1受体激动剂可复制电针的镇痛效果。
我们的结果表明腺苷介导的P物质分泌受到调节。P物质介导的途径可能参与了大鼠电针镇痛过程。
