Orientin and neuropathic pain in rats with spinal nerve ligation.

Neuropathic pain affects patients worldwide. The therapeutic effects of current methods are still poor. This study was performed to investigate the neuro-protective effect of orientin in rats with spinal nerve ligation (SNL). In this study, the paw mechanical withdrawal threshold (PWT) and the paw thermal withdrawal latency (PWL) behavioral assays indicated that orientin alleviated the warm and mechanical allodynia in rats with SNL. The enzyme-linked immunosorbent assay (ELISA) showed that orientin suppressed the levels of pro-inflammatory cytokines interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor alpha (TNF-α) and increased the levels of anti-inflammatory cytokine interleukin-10 (IL-10). Malondialdehyde (MDA) levels were down-regulated while superoxide dismutase (SOD) and glutathione (GSH) levels were up-regulated by orientin. OX42 and GFAP immune fluorescent staining results demonstrated that orientin inhibited the activation of microglia and astrocytes in rats with SNL. Western blot analysis indicated that the neuroprotective effect of orientin was mediated by inhibition of Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-kappa B) signaling pathway. This study suggested that orientin is a promising neuroprotective agent suitable for therapy for neuropathic pain.