Thymol gel ameliorates anesthesia-related postoperative neuropathic pain: modulation of inflammatory mediators in a rat model.

This study investigated the molecular mechanisms and therapeutic efficacy of chitosan-based thymol gels (2.5%, 5%, and 10%) in postoperative neuropathic pain. Gels exhibited pseudoplastic shear-thinning behavior and a biphasic release profile, achieving > 90% cumulative release within 12 h. Using a Wistar rat model of hind paw incision, topical treatment with 5% and 10% thymol gels significantly (P < .05) reversed the reduction in paw withdrawal latency and threshold compared to the controls. Thymol gel markedly decreased serum corticosterone, cyclooxygenase-2 (COX-II), and prostaglandin E2 (PGE2) levels. Furthermore, it downregulated the messenger ribonucleic acid (mRNA) expression of interleukins and tumor necrosis factor in the sciatic nerve. Histopathological analysis confirmed reduced inflammation and congestion. Positive correlations were observed between pro-inflammatory cytokine expression and serum corticosterone, PGE2, and COX-II levels. These findings suggest that thymol gel effectively ameliorates anesthesia-related postoperative neuropathic pain by modulating key inflammatory mediators, suggesting its beneficial treatment option for alleviating such pain.