Tuina Alleviates Neuropathic Pain in Cervical Radiculopathy by Inhibiting Central Sensitization via the Microglial P2X4R/BDNF/TRKB Pathway

Objective To investigate the analgesic effect of Tuina (therapeutic massage) on neuropathic pain associated with cervical spondylotic radiculopathy (CSR) in rats and to examine its regulatory effects on spinal microglial activation, the P2X4R/BDNF/TRKB signaling pathway, and central sensitization. Methods Adult male Sprague Dawley rats were randomly assigned to five groups ( n = 10 per group): control (Ctrl), CSR model (model), Tuina (TN), microglial inhibitor (MI), and Tuina + microglial inhibitor (TN + MI). A CSR-associated neuropathic pain model was established by chronic cervical nerve root compression, which induces persistent radicular pain-like behavior and motor dysfunction. Tuina was applied to the cervical region once daily for 10 min in the TN and TN + MI groups. Minocycline, a microglial inhibitor, was administered via intrathecal injection from day 8 to day 21 after model establishment in the MI and TN + MI groups. Paw withdrawal mechanical threshold (PWMT), paw withdrawal thermal latency (PWTL), and gait score were used to evaluate pain behavior and motor function. The expression of TRKB in the spinal dorsal horn was detected by immunohistochemistry. P2X4R and BDNF were assessed by immunofluorescence. Protein levels of P2X4R, BDNF, and TRKB were measured by Western blot. mRNA expression of NMDAR and AMPAR was determined by qRT-PCR. Results Compared with the control group, the model group showed significantly decreased PWMT, PWTL, and gait scores, along with marked increases in P2X4R, BDNF, and TRKB protein levels and NMDAR and AMPAR mRNA expression (all P < 0.01), indicating pronounced neuropathic pain and central sensitization. The TN and MI groups also differed from the control group (all P < 0.05), whereas the TN + MI group exhibited only slight, nonsignificant deviations from the control. Compared with the model group, both TN and MI interventions significantly improved behavioral parameters (PWMT, PWTL, gait score) and reduced the expression of TRKB, P2X4R, BDNF, NMDAR, and AMPAR (all P < 0.05), with more robust effects in the TN + MI group (all P < 0.01). Conclusion Tuina alleviates pain behavior and motor dysfunction in CSR-associated neuropathic pain in rats, likely by inhibiting microglial activation, suppressing the P2X4R/BDNF/TRKB signaling pathway, and reducing NMDAR/AMPAR-related central sensitization. Combination with microglial inhibition produces superior behavioral and molecular effects, suggesting that Tuina, alone or in conjunction with microglia-targeted therapies, may represent a promising strategy for the management of CSR-related neuropathic pain.