Increased expression of interleukin-18 in the trigeminal spinal subnucleus caudalis after inferior alveolar nerve injury in the rat

► A trigeminal neuropathic pain model was used with inferior alveolar nerve transection. ► IL-18 upregulation occurred in hyperactive microglia in the trigeminal spinal subnucleus caudalis. ► IL-18 was increased in the Vc around obex area from 3 d until 14 d after nerve injury. ► IL-18 induction coexisted with phosphorylated p38 MAPK. ► The findings suggest a role of IL-18 in orofacial neuropathic pain mechanism.