α-Asarone attenuates chronic sciatica by inhibiting peripheral sensitization and promoting neural repair

This study explored the therapeutic effect of alpha-asarone on chronic sciatica. Thirty-two Sprague-Dawley (SD) rats were divided into four groups: the sham group, chronic constriction injury (CCI) group, pregabalin group, and alpha-asarone group. Hot hyperalgesia was induced after the CCI operation, and alpha-asarone was found to relieve chronic neuralgia. Furthermore, alpha-asarone reduced IL1 beta, IL6, TNF-alpha, CRP, and LPS levels and increased IL10 levels in serum. alpha-Asarone decreased the protein levels of TRPA1, TRPM8, and TRPV1-4 and the mRNA levels of TRPA1, TRPM8, TRPV1-4, IL1 beta, and TNF-alpha in dorsal root ganglion neurons. In the sciatic nerve, alpha-asarone treatment reduced the number of inflammatory cells and promoted the proliferation of Schwann cells, favouring recovery of the nerve structure. In cellular experiments, LPS induced Schwann cell apoptosis via TLR4/p38MAPK signalling; alpha-asarone attenuated LPS-induced Schwann cell apoptosis by decreasing TLR4, p-p38MAPK, cleaved-caspase3, and cleaved-caspase7 levels and increasing Bcl-2 and Bcl-xl expression. Overall, these findings suggest that alpha-asarone relieves chronic sciatica by decreasing the levels of inflammatory factors, inhibiting peripheral sensitization, and favouring the repair of damaged nerves.