Abstract:Photothrombotic ischemia is a common experimental ischemic stroke model. In response to light stimulation, activated photosensitive dyes produce reactive oxygen species, which in turn induces damage to the vascular endothelial cells, causing platelet adhesion, aggregation and thrombosis. Since the conventional photothrombotic ischemia model produces only a tiny ischemic penumbra which can’t properly represent the clinical pathology, a modified proximal middle cerebral artery occlusion model was established in this study. The mouse proximal middle artery was irradiated by laser for 3 minutes to induce thrombosis following injection with the light-sensitive dye Rose Bengal and subsequently evaluated by 2,3,5-triphenyltetrazolium chloride staining, immunofluorescence, and flow cytometry. The results showed that this model produced a stable infarct area of 9% to 15% in the striatal and cortical regions, which is larger than the conventional photothrombotic ischemia. Resident microglia, infiltrating myeloid cells, and lymphocytes in the infarcted tissue were identified by flow cytometry. It is suggested that the modified proximal middle artery occlusion model can be applied to study the pathological and immune mechanisms after ischemic stroke injury.