IL1B and peripheral nerve injury: In case of peripheral nerve injury, the damaged neurons send excitatory signals to the spinal microglia via chemical substances, such as ATP and chemokines; these, in turn, cause microglial proliferation and upregulation of inflammatory cytokines, such as TNF-α, IL-1β, and IL-6, resulting in NP (Milligan and Watkins, 2009; Zhao et al., 2017).