Inhibition Of NF-κB Activation Is Associated With Anti-inflammatory And Anti-apoptotic Effects Of Ginkgolide B In A Mouse Model Of Cerebral Ischemia/Reperfusion Injury

Aim:To investigate the effects of Ginkgolide B (GB) on ischemia/reperfusion induced brain injury, NF-κB activation, inflammatory response and apoptosis.Methods:Transient middle cerebral artery occlusion (tMCAO) was produced by using an intraluminal filament technique in mice. GB (10,20and40mg/kg) was intravenously (i.v.) administered immediately after reperfusion (2h after MCAO). The neuroprotective effects of GB was analyzed by scoring neurological deficits, assessing brain infarction volume with2,3,5-triphenyltetrazolium chloride (TTC) and determining the brain water content24h after reperfusion. Brain sections were immunostained for NF-κB p65nuclear translocation and microglia activation in cerebral cortex. RT-PCR was used to measure TNF-α, IL-1β and iNOS mRNA levels in cerebral cortex. Western blot analysis was employed to determine alterations in IκBα, p-IκBα, p-IKKα, p53, Bcl-2, Bax and Caspase3in cerebral cortex at the indicated time.Results:GB (10,20and40mg/kg) reduced infarction volume in a dose-dependent manner (P<0.05, P<0.01). GB also significantly ameliorated motor behavior deficits, diminished the increase in brain water content (P<0.05). Western blot analysis revealed that MCAO-induced cerebral injury was accompanied by a degradation of IκBα and up-regulation of p-IKKα, p-IKBα, indicating activation of NF-κB. GB markedly inhibited the degradation of IκBα and up-regulation of p-IKKa, p-IκBα (P<0.05, P<0.01). Immunofluorescence analysis demonstrated that GB markedly inhibited ischemia/reperfusion induced NF-κB nuclear translocation3h after reperfusion and microglia activation2d after reperfusion. RT-PCR analysis revealed that GB significantly suppressed the ischemia/reperfusion induced increase in expression of TNF-α, IL-1β and iNOS mRNA in cerebral cortex2d after reperfusion (P<0.05, P<0.01). Western blot analysis also revealed that MCAO-induced cerebral injury was associated with an up-regulation of p53, Bax, Caspase3and down-regulation of Bcl-2in cerebral cortex at12h after reperfusion. GB markedly inhibited the ischemia/reperfusion induced up-regulation of p53, Bax, Caspase3levels and down-regulation of Bcl-2level (P<0.05, P<0.01)。Conclusion:The present findings provide the evidence that Ginkgolide B has neuroprotective activity on cerebral ischemia/reperfusion injury, and this effect may be attributable to its anti-inflammatory and anti-apoptotic effect through inhibition of NF-κB.