TIGAR Inhibits Ischemia/Reperfusion-Induced Inflammatory Response Of Astrocytes

Aim: To observe the protective effect of TIGAR on astrocytes; the influence of TIGAR on ischemia/reperfusion induced NF-κB activation and ischemic inflammation.Method: To investigate the effects of TIGAR, transient middle cerebral artery occlusion(tMCAO) in mice and the OGD/reperfusion model of astrocytes in vitro was used. In vitro the changes in expression of TIGAR was analyzed with Western blot analysis. In animal model, TIGAR expression in astrocytes was detected with immunefluorescence analysis. Adenovirus-mediated overexpression or knockdown of TIGAR was conducted in primary cortical astrocytes, the protection of TIGAR on OGD/R induced astrocytes death was detected with CCK-8 and LDH. Elisa and Western blot analysis were used to measure TNF-α, IL-1β and iNOS, COX-2 protein levels in cells and animals models. Western blot analysis was employed to determined alterations in IκB, p-IκB and NF-κB in cultured astrocytes at indicated time.Results:Ischemia-reperfusion induced increasing in the expression of TIGAR in astrocytes. CCK-8 and LDH assays showed that overexpression of TIAGR could significantly reduce astrocytes death induced by OGD/R. Interference TIGAR aggravated the injury of astrocytes induced by OGD/R. Elisa and Western blot analysis revealed that overexpression of TIAGR significantly suppressed the OGD/R or ischemia/reperfusion induced increase in expression in TNF-α, IL-1β and iNOS, COX-2. Western blot analysis revealed that OGD-induced cell death was accompanied by degradation of IκB and up-regulation of p-IκB, indicating activation of NF-κB. Overexpression of TIAGR markedly inhibited degradation of IκB, up-regulation of p-IκB and NF-κB nuclear translocation 1 h after reoxygenation.Conclusion : TIGAR has a protective effect for astrocytes against ischemia-reperfusion injury, its mechanism may be related to enhance endogenous antioxidant NADPH, reduce inflammation response by inhibiting activation of NF-κB.