TNF and peripheral nerve injury: H2S has an anti-inflammatory effect, alleviating mechanical allodynia and thermal hyperalgesia, by reducing nuclear factor-kappa B (NF-κb) expression and the excessive inflammatory cytokines tumor necrosis factor (TNF-α), interleukins IL-1β and IL-6, and high mobility group box (HMGB-1) in the spinal cord after peripheral nerve injury via the nuclear factor erythroid-2 (Nrf2)/hemeoxygenase-1 (HO-1) pathway in the microglial cells (Chen et al., 2019).