We established an in vivo model of cerebral ischemia stimulated by photochemistry and an oxygen–glucose deprivation (OGD)-induced PC12 cells model in vitro, combined with the pretreatment of L-NAME, an inhibitor of NOS, to explore the effects of NO/NOS signaling on oxidative stress and apoptosis in vivo and in vitro. The gene discussed is NOS2; the disease is Cerebral ischemia.