Introduction: Sciatica causes intense pain. No satisfactory therapeutic drugs exist to treat sciatica. This study aimed to probe the potential mechanism of ferulic acid in sciatica treatment.Methods: Thirty‐two SD rats were randomly divided into 4 groups: sham operation, chronic constriction injury (CCI), mecobalamin, and ferulic acid. We conducted RNA sequencing, behavioral tests, ELISA, PCR, western blotting, and immunofluorescence analysis. TAK‐242 and JSH23 were administered to RSC96 and GMI‐R1 cells to explore whether ferulic acid can inhibit apoptosis and alleviate inflammation.Results: RNA sequencing showed that TLR4/NF‐κB pathway is involved in the mechanism of sciatica. CCI induced cold and mechanical hyperalgesia; destroyed the sciatic nerve structure; increased IL‐1β, IL‐6, TNF‐α, IL‐8, and TGF‐β protein levels and IL‐1β, IL‐6, TNF‐α, TGF‐β, TLR4, and IBA‐1 mRNA levels; and decreased IL‐10 and INF‐γ protein levels and IL‐4 mRNA levels. Immunohistochemistry showed that IBA‐1, CD32, IL‐1β, iNOS, nNOS, COX2, and TLR4 expression was increased while S100β and Arg‐1 decreased. CCI increased TLR4, IBA‐1, IL‐1β, iNOS, Myd88, p‐NF‐κB, and p‐p38MAPK protein levels. Treatment with mecobalamin and ferulic acid reversed these trends. Lipopolysaccharide (LPS) induced RSC96 cell apoptosis by reducing Bcl‐2 and Bcl‐xl protein and mRNA levels and increasing Bax and Bad mRNA and IL‐1β, TLR4, Myd88, p‐NF‐κB, and p‐p38MAPK protein levels, while ferulic acid inhibited cell apoptosis by decreasing IL‐1β, TLR4, Myd88, p‐NF‐κB, and p‐p38MAPK levels and increasing Bcl‐2 and Bcl‐xl levels. In GMI‐R1 cells, Ferulic acid attenuated LPS‐induced M1 polarization by decreasing the M1 polarization markers IL‐1β, IL‐6, iNOS, and CD32 and increasing the M2 polarization markers CD206, IL‐4, IL‐10 and Arg‐1. After LPS treatment, IL‐1β, iNOS, TLR4, Myd88, p‐p38MAPK, and p‐NF‐κB levels were obviously increased, and Arg‐1 expression was reduced, while ferulic acid reversed these changes.Conclusion: Ferulic acid can promote injured sciatic nerve repair by reducing neuronal cell apoptosis and inflammatory infiltration though the TLR4/NF‐κB pathway.

Background: This study aimed to investigate the potential mechanism of paeonol in the treatment of neuropathic pain.Methods: Relevant mechanisms were explored through microglial pseudotime analysis and the use of specific inhibitors in cell experiments. In animal experiments, 32 SD rats were randomly divided into the sham operation group, the chronic constrictive injury (CCI) group, the ibuprofen group, and the paeonol group. We performed behavioral testing, ELISA, PCR, Western blotting, immunohistochemistry, and immunofluorescence analysis.Results: The pseudotime analysis of microglia found that RhoA, Rock1, and p38MAPK were highly expressed in activated microglia, and the expression patterns of these genes were consistent with the expression trends of the M1 markers CD32 and CD86. Paeonol decreased the levels of M1 markers (IL1β, iNOS, CD32, IL6) and increased the levels of M2 markers (IL10, CD206, ARG‐1) in LPS‐induced microglia. The expression of iNOS, IL1β, RhoA, and Rock1 was significantly increased in LPS‐treated microglia, while paeonol decreased the expression of these proteins. Thermal hyperalgesia occurred after CCI surgery, and paeonol provided relief. In addition, paeonol decreased the levels of IL1β and IL8 and increased the levels of IL4 and TGF‐β in the serum of CCI rats. Paeonol decreased expression levels of M1 markers and increased expression levels of M2 markers in the spinal cord. Paeonol decreased IBA‐1, IL1β, RhoA, RhoA‐GTP, COX2, Rock1, and p‐p38MAPK levels in the spinal dorsal horn.Conclusion: Paeonol relieves neuropathic pain by modulating microglial M1 and M2 phenotypes through the RhoA/p38 MAPK pathway.

Aims: This study aimed to investigate the potential therapeutic applications of stigmasterol for treating neuropathic pain.Methods: Related mechanisms were investigated by DRG single‐cell sequencing analysis and the use of specific inhibitors in cellular experiments. In animal experiments, 32 male Sprague–Dawley rats were randomly divided into the sham operation group, CCI group, ibuprofen group, and stigmasterol group. We performed behavioral tests, ELISA, H&E staining and immunohistochemistry, and western blotting.Results: Cell communication analysis by single‐cell sequencing reveals that after peripheral nerve injury, Schwann cells secrete IL‐34 to act on CSF1R in macrophages. After peripheral nerve injury, the mRNA expression levels of CSF1R pathway and NLRP3 inflammasome in macrophages were increased in DRG. In vitro studies demonstrated that stigmasterol can reduce the secretion of IL‐34 in LPS‐induced RSC96 Schwann cells; stigmasterol treatment of LPS‐induced Schwann cell‐conditioned medium (L‐S‐CM) does not induce the proliferation and migration of RAW264.7 macrophages; L‐S‐CM reduces CSF1R signaling pathway (CSF1R, P38MAPK, and NFκB) activation, NLRP3 inflammasome activation, and ROS production. In vivo experiments have verified that stigmasterol can reduce thermal and cold hyperalgesia in rat chronic compressive nerve injury (CCI) model; stigmasterol can reduce IL‐1β, IL‐6, TNF‐α, CCL2, SP, and PGE2 in serum of CCI rats; immunohistochemistry and western blot confirmed that stigmasterol can reduce the levels of IL‐34/CSF1R signaling pathway and NLRP3 inflammasome in DRG of CCI rats.Conclusion: Stigmasterol alleviates neuropathic pain by reducing Schwann cell‐macrophage cascade in DRG by modulating IL‐34/CSF1R axis.

Therapeutic drugs of chronic neuralgia have a high risk of addiction, making it crucial to identify novel drugs for chronic neuralgia. This study aimed to explore the therapeutic effect of paeoniflorin on chronic sciatica via inhibiting Schwann cell apoptosis. 28 SD rats were randomly divided into four groups, including the sham operation group, chronic constriction injury (CCI) group, mecobalamin group, and paeoniflorin group. The therapeutic effect and mechanism of paeoniflorin were evaluated via rat and cell experiments. Mechanical, hot, or cold hyperalgesia was induced in the rats after CCI operation, while paeoniflorin relieved chronic neuralgia. Besides, paeoniflorin decreased the levels of IL1, IL6, TNF‐α, CRP, and LPS and increased the level of IL10 in serum. As for the sciatic nerve, the number of inflammatory cells was decreased, and Schwann cells were present after paeoniflorin treatment, and paeoniflorin promoted the recovery of nerve structure. In cell experiments, LPS induced Schwann cell apoptosis via the TLR4/NF‐kB pathway. And paeoniflorin attenuated LPS‐induced Schwann cell apoptosis by decreasing the levels of TLR4, p‐NF‐kB, caspase3, cleaved‐caspase3, and cleaved‐caspase7. Overall, these results suggest that paeoniflorin alleviates chronic sciatica by decreasing inflammatory factor levels and promotes the repair of damaged nerves by reducing Schwann cell apoptosis.