Tuina alleviates neuropathic pain through regulate the activation of microglia and the secretion of inflammatory cytokine in spinal cord.

Objective: To observe the analgesic effects of Tuina on neuropathic pain (NPP) and the underlying mechanisms.

Methods: Forty-eight Sprague-Dawley (SD) rats were assigned by random into three treatment groups: sham, chronic constriction injury (CCI), and Tuina. Each group contained sixteen rats. CCI model was generated by ligating the right sciatic nerve. Behavioral changes of CCI were assessed by the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). In addition, biochemical techniques such as immunofluorescence staining, enzyme-linked immunosorbent assay (ELISA) and Western blotting were used to profile levels of microglia activation and inflammatory factors in the spinal dorsal horn (SDH) of rats. Tuina (clockwise pressing and rubbing) was performed at Chengshan (BL57) to observe the analgesic effects on CCI rats and the underlying mechanisms.

Results: Rats with CCI experienced significant reduction in the PWT and PWL of the right hind paw relative to CCI group at day 3. Tuina treatment rescued this situation significantly on days 10 and 14. Besides, Iba-1, microglia M1 receptor CD68, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were higher in the right SDH for CCI group compared to the sham group on day 14. As expected, Tuina partially downregulated the CCI-induced overexpressed Iba-1, CD68, TNF-α, and IL-1β in the SDH of CCI model.

Conclusion: Tuina induces a time-dependent cumulative analgesic effect in CCI rats by inhibiting the activation of microglia and the secretion of IL-1β and TNF-α in SDH.