Acupuncture relieves postoperative pain of mixed hemorrhoids through the P2X7/ERK axis in Dorsal root ganglion

Haemorrhoids are a common anorectal disease primarily treated through surgery, often leading to complications such as pain. The efficacy of acupuncture in relieving postoperative pain in mixed haemorrhoids has not been well-documented. This study included 90 patients undergoing haemorrhoid surgery and their Visual Analogue Score (VAS), inflammatory factor levels, Hamilton Depression Rating Scale (HAMD), and analgesic drug use were accessed. A rat incisional pain model was also constructed to monitor behavioral responses, with assessments including Sucrose Preference Test (SPT) and Open Field Test (OFT). The levels of ATP and proinflammatory cytokines in the dorsal root ganglion (DRG) were measured using luciferase assay and ELISA. We also examined P2X7 and ERK1/2 levels in DRG tissues of anal incisional pain rat model. In a Chronic Constriction Injury (CCI) rat model treated with BzATP, a potent agonist for P2X7 receptors, followed by acupuncture for 15 days, postoperative pain and behavioral responses were observed and assessed, alongside mechanistic studies of ATP and inflammatory factors in DRG tissues. Patients receiving acupuncture had significantly lower VAS scores, reduced levels of inflammatory factors, improved depression scores, and decreased analgesic drug use. In the animal model, acupuncture increased pain thresholds, improved behavioral responses, reduced ATP content and inflammatory factors, and modulated the P2X7/ERK axis. In the CCI model, BzATP increased P2X7 and ERK1/2 levels, pain sensitivity, and anxiety, which were mitigated by acupuncture. Our data suggest that acupuncture significantly alleviates postoperative pain following haemorrhoid surgery and modulates the pain response through the P2X7/ERK axis.