Hong Shou-Hai, Ding Sha-Sha, Xu Yuan, Zhang Kuo, Zhao Xue, Liu Yang-Yang, Xuan Li-Hua, Guo Yong-Ming, Guo Yi
Acupuncture Department, Zhejiang Provincial Hospital of TCM, Hangzhou, China.
Acupuncture Physiotherapy Department, Rehabilitation Department, Tianjin Nankai Hospital, Tianjin, China.
Acupunct Med. 2021 Dec;39(6):673-680. doi: 10.1177/0964528421997435. Epub 2021 Mar 11.
Inflammatory pain is the most common type of pain encountered clinically. The analgesic effect of acupuncture has been well-documented.
The aim of this study was to investigate the involvement of chemokine CXCL1 in the serum on manual acupuncture (MA)-induced antinociception.
Rats with inflammatory pain of the right hind paw were induced by intraplantar (i.pl.) administration of complete Freund's adjuvant (CFA). After wards, the CFA-injected rats were treated daily with MA at ST36 from Day 1 to Day 7, and thermal nociceptive thresholds (paw withdrawal latency; PWL) were analyzed. The concentration of CXCL1 in the serum of the rats was measured by enzyme-linked immunosorbent assay (ELISA) after the first and the last MA treatment. Subsequently, the rats were injected with two doses (5 or 10 μg) of recombinant CXCL1 through the tail vein daily from Day 1 to Day 7 or injected with two doses (6.4 or 16 μg) of anti-CXCL1 antibody using the same methods and course at 30 min before MA, and the PWLs were measured again. Finally, naloxone (500 μg, 0.1 mL) was administered by i.pl. injection into the inflamed paw 5 min before the last MA treatment or last injection of recombinant CXCL1.
MA significantly increased the PWLs and upregulated the expression of serum CXCL1 in the CFA-injected rats. Without acupuncture, repeated tail vein injection of recombinant CXCL1 showed an analgesic effect on CFA-induced inflammatory pain. Conversely, the neutralization of serum CXCL1 by anti-CXCL1 antibody decreased MA-induced antinociception in a time-dependent manner. Anti-CXCL1 antibody injected just once before the first MA did not affect MA-induced antinociception. The analgesic effects of MA and recombinant CXCL1 were reversed by an i.pl. injection of naloxone.
This study indicates MA at ST36 had an analgesic effect on inflammatory pain and found a novel function of CXCL1. Increased serum CXCL1 had an antinociceptive effect on inflammatory pain induced by CFA. CXCL1 in serum appeared to be a key molecule involved in the peripheral mechanism of MA-induced antinociception. The analgesic effect of MA or recombinant CXCL1 on inflammatory pain might be mediated through a peripheral opioid pathway, which needs further investigation.
炎性疼痛是临床上最常见的疼痛类型。针刺的镇痛作用已有充分记录。
本研究旨在探讨趋化因子CXCL1在血清中是否参与了手针（MA）诱导的抗伤害感受作用。
通过右后足底注射完全弗氏佐剂（CFA）诱导大鼠右后爪出现炎性疼痛。之后，从第1天至第7天，每天对注射CFA的大鼠进行足三里穴手针治疗，并分析热痛觉阈值（缩爪潜伏期；PWL）。在首次和末次手针治疗后，采用酶联免疫吸附测定（ELISA）法检测大鼠血清中CXCL1的浓度。随后，从第1天至第7天，每天经尾静脉给大鼠注射两剂（5或10μg）重组CXCL1，或在每次手针治疗前30分钟，采用相同方法和疗程给大鼠注射两剂（6.4或16μg）抗CXCL1抗体，再次测量PWL。最后，在末次手针治疗或末次注射重组CXCL1前5分钟，经右后足底注射纳洛酮（500μg，0.1mL）。
手针对注射CFA的大鼠具有显著提高PWL和上调血清CXCL1表达的作用。在未进行针刺的情况下，重复经尾静脉注射重组CXCL1对CFA诱导的炎性疼痛具有镇痛作用。相反，抗CXCL1抗体中和血清CXCL1可使手针诱导的抗伤害感受作用呈时间依赖性降低。仅在首次手针治疗前注射一次抗CXCL1抗体并不影响手针诱导的抗伤害感受作用。经右后足底注射纳洛酮可逆转手针和重组CXCL1的镇痛作用。
本研究表明，足三里穴手针治疗对炎性疼痛具有镇痛作用，并发现了CXCL1的新功能。血清CXCL1水平升高对CFA诱导的炎性疼痛具有抗伤害感受作用。血清中的CXCL1似乎是参与手针诱导抗伤害感受外周机制的关键分子。手针或重组CXCL1对炎性疼痛的镇痛作用可能是通过外周阿片类途径介导的，这有待进一步研究。
