Kang Suk-Yun, Bang Se Kyun, Seo Su Yeon, Cho Seong Jin, Choi Kwang-Ho, Han Sangeun, Ryu Yeonhee
Korea Institute of Oriental Medicine, Daejeon 34054, Republic of Korea.
Int J Mol Sci. 2025 Sep 2;26(17):8534. doi: 10.3390/ijms26178534.
We recently developed a mechanical acupuncture instrument (MAI) that applies mechanical stimulation to acupuncture points in effectively treating hypertension and addiction in animal models. However, its analgesic effect on inflammatory pain remains unclear. Here, we aimed to determine the optimal duration of MAI treatment at any given acupuncture point to improve analgesic effects. Adult male ICR mice (20-25 g, 6 weeks old, n = 6 per group) were used to evaluate whether MAI administration or TRPV1 (transient receptor potential vanilloid 1) inhibition had analgesic effects. Then, we investigated whether it affected TRPV1 expression and glial cells in the spinal cord of mice. The capsaicin test was used to identify the most effective acupoints and optimal treatment times for MAI. Additionally, we induced inflammatory pain in mice by administering a 2% carrageenan via intraplantar injection. To assess the analgesic effects of MAI treatment and TRPV1 inhibition, we evaluated pain-related behavior using von Frey filaments and a thermal stimulator applied to the hind paw. MAI treatment significantly suppressed pain-related behaviors. In particular, paw-licking duration was markedly reduced in the group treated with MAI for 60 s at ST36 compared to the capsaicin-treated group ( < 0.05), suggesting a robust analgesic effect. Additionally, MAI and capsazepine administration significantly attenuated carrageenan-induced mechanical allodynia and thermal hyperalgesia compared to the carrageenan-only group ( < 0.05 to < 0.001). Additionally, MAI treatment and capsazepine administration effectively suppressed the carrageenan-induced upregulation of TRPV1 and glial cells in the spinal cord. In conclusion, our findings show that MAI administration at ST36 significantly alleviated inflammatory pain and was associated with downregulation of TRPV1 expression and microglial activation in the spinal cord. The present findings suggest that TRPV1 signaling is involved in the analgesic effects of mechanical acupuncture; however, a direct causal relationship has yet to be established.
我们最近研发了一种机械针灸仪器（MAI），该仪器通过对穴位施加机械刺激，在动物模型中有效治疗高血压和成瘾。然而，其对炎性疼痛的镇痛效果仍不清楚。在此，我们旨在确定在任何给定穴位进行MAI治疗的最佳持续时间，以提高镇痛效果。使用成年雄性ICR小鼠（20 - 25克，6周龄，每组n = 6）来评估MAI给药或TRPV1（瞬时受体电位香草酸亚型1）抑制是否具有镇痛作用。然后，我们研究了其是否影响小鼠脊髓中的TRPV1表达和胶质细胞。辣椒素试验用于确定MAI最有效的穴位和最佳治疗时间。此外，我们通过足底注射2%角叉菜胶在小鼠中诱导炎性疼痛。为了评估MAI治疗和TRPV1抑制的镇痛效果，我们使用von Frey细丝和应用于后爪的热刺激器评估疼痛相关行为。MAI治疗显著抑制了疼痛相关行为。特别是，与辣椒素治疗组相比，在ST36处接受MAI治疗60秒的组中舔爪持续时间明显缩短（<0.05），表明具有强大的镇痛效果。此外，与仅用角叉菜胶处理的组相比，MAI和capsazepine给药显著减轻了角叉菜胶诱导的机械性异常性疼痛和热痛觉过敏（<0.05至<0.001）。此外，MAI治疗和capsazepine给药有效抑制了角叉菜胶诱导的脊髓中TRPV1和胶质细胞的上调。总之，我们的研究结果表明，在ST36处进行MAI给药可显著减轻炎性疼痛，并与脊髓中TRPV1表达下调和小胶质细胞激活有关。目前的研究结果表明，TRPV1信号传导参与了机械针灸的镇痛作用；然而，直接的因果关系尚未确立。
