Fig. 5

Red nucleus IL-33 facilitates the early development of mononeuropathic pain by activating p38 MAPK signaling pathway. A Western blotting showed an upregulated p-p38 MAPK in the RN at 1 week post-SNI, intrarubral administration of anti-IL-33 antibody restrained the increase of p-p38 MAPK (n = 6 per group, F = 13.002, P < 0.001). B Western blotting demonstrated that intrarubral injection of IL-33 stimulated the protein expression of p-p38 MAPK in naive rats (n = 6 per group, F = 18.974, P < 0.001). C Immunohistochemistry showed that p-p38 MAPK was increased in the RN of SNI rats (F = 88.711, P < 0.001) and IL-33-induced hypersensitivity rats (F = 27.208, P < 0.001) (n = 4 per group). D Intrarubral administration of p38 MAPK inhibitor SB203580 at 1 week post-injury attenuated SNI-induced mononeuropathic pain compared to DMSO control (n = 5–6 per group, F = 51.310, P < 0.001). E SB203580 pre-injected into the RN, 30 min ahead of IL-33 administration, relieved IL-33-evoked mechanical hypersensitivity compared to DMSO control (n = 5-6 per group, F = 39.381, P < 0.001). *P < 0.05, **P < 0.01, and ***P < 0.001. Scale bars = 50 μm