Infiltration And Persistence Of Lymphocytes During Late-stage Cerebral Ischemic In Middle Cerebral Occlusion And Photothrombotic Stroke

Infiltrating lymphocytes participate in brain injury and repair after ischemia.Several animal models have been used to study lymphocytes-mediated immune and inflammatory responses after cerebral ischemia,however,detailed knowledge is lacking in terms of the neuronflammatory profiles among these models during the late stage of ischemic brain injury,as well as their potential relevance to human stroke.In this study,we compared the similarities and differences in the immune and inflammatory features during late-stage ischemic stroke induced by photothrombosis or trainsient middle cerebral artery occlusion in mice.At day 14 after onset,we found that brain infarct persists in mice subjected to photothrombotic stroke.In constrast,brain infarct is insignificant in mice subjected to MCAO.ROS production was seen at day 14 in photothrombotic stroke mice,along with the lymphocytes infiltration especially IFN-y-expressed CD4+T cell accumulation.More proliferated neuronal precursor cells and GFAP+ cells were observed around perilesional area in photothrombosis mice,which may participate in the late phase of brain ischemia and neurogenesis.Using brain tissue of stroke patients,photothrombosis model was demonstrated to better mimicked the inflammatory brain infiltration in ischemia stroke patients.Our study demonstrated that photothrombotic model is more feasible for long-term assessment and post-ischemia recovery study,and lymphocytes activation driving immune response may involve in late stage of brain ischemia.