Fig. 9

Red nucleus IL-33 evokes mechanical hypersensitivity by inducing TNF-α through activating ERK, p38 MAPK, and JAK2/STAT3 signaling pathways. A Western blotting indicated that intrarubral administration of IL-33 stimulated the secretion of TNF-α in naive rats (n = 6 per group, F = 15.143, P < 0.001). B Western blotting showed that intrarubral pre-injection of PD98059, SB203580, or AG490, 30 min before IL-33 administration, restrained IL-33-induced overexpression of TNF-α in naive rats (n = 6 per group, F = 9.812, P < 0.001). C Immunohistochemistry showed that intrarubral injection of IL-33 potentiated the secretion of TNF-α in naive rats, intrarubral pre-injection of PD98059, SB203580, or AG490, 30 min prior to IL-33 administration, inhibited IL-33-induced overexpression of TNF-α in naive rats (n = 4 per group, F = 44.310, P < 0.001). *** P < 0.001. Scale bars = 50 μm