Fisetin has Inhibitory Effects on the TLR 4/NF-κB-Mediated Inflammatory Pathway After Traumatic Brain Injury in Mice: A Potential Neuroprotective Role

Inflammatory response contributes to the high mortality and morbidity of traumatic brain injury (TBI). Potent anti-inflammatory effects can alleviate brain injury after TBI. Fisetin has anti-inflammatory properties in several brain injury models, but the effects of fisetin on inflammation after TBI is still unclear. Our study aimed to investigate the neuroprotective effects of fisetin against inflammation after TBI in mice.Fisetin (25 mg/kg, 50 mg/kg or 75 mg/kg) or equal volume of vehicle was given via intraperitoneal injection 30 min after TBI. The neurological severity score, brain edema and blood brain barrier (BBB) permeability were assayed after TBI. In further mechanistic studies, changes in the toll-like receptor 4 (TLR 4)/nuclear factor-κB (NF-κB) pathway and the expression of pro-inflammatory cytokines were measured. Fisetin significantly improved behavioral outcomes and reduced brain edema after TBI. These changes were associated with significant reductions in TLR 4 expression and NF-κB activity. In addition, changes in the expression of pro-inflammatory cytokines were detected 24 h after TBI. Our study provided the first evidence that fisetin exerted neuroprotective effects by inhibiting the TLR 4/NF-κB–mediated inflammatory pathway after TBI in mice.