Time dependent Change of In Vivo Optical Imaging of Oxidative Stress in a Mouse Stroke Model

Nuclear factor elythroid 2-related factor 2 (Nrf2) plays a pivotal role in cellular defense against oxidative stress damage after ischemic stroke. In the present study, we examined the tinne-dependent change of in vivo optical imaging of oxidative stress after stroke with Keap1-dependent oxidative stress detector (OKD) mice. OKD mice were subjected to transient middle cerebral artery occlusion (tMCAO) for 45 min, and in vivo optical signals were detected during the pre-operative period, 12h, 1 d, 3 d, and 7 d after tMCAO. Ex vivo imaging was performed immediately after obtaining in vivo optical signals at 1 d after tMCAO. Imnnunohistochemical analyses and infarct volume were also examined after in vivo imaging at each period. The in vivo signals showed a peak at 1 d after tMCAO that was slightly correlated to infarct volume. The strong ex vivo signals, which were detected in the periischemic area, corresponded to endogenous Nrf2 expression. Moreover, endogenous Nrf2 expression was detected mainly in neurons followed by oligodendrocytes and pericytes, but only slightly in astrocytes, microglia, endothelial cells. The present study successfully demonstrated the temporal change of in vivo imaging of oxidative stress after tMCAO, which is consistent with strong expression of endogenous Nrf2 in the peri-ischennic area with a similar time course. (C) 2017 Wiley Periodicals, Inc.