Differential Study Of Cerebral Blood Flow Changes In Mice With Different Time Windows Of Middle Cerebral Artery Embolization And Reperfusion And Reperfusion

Middle cerebral artery occlusion(MCAO)is a cerebrovascular disease with high clinical morbidity and mortality.Patients need to receive rtPA thrombolytic therapy within the treatment time window,otherwise it will lead to hemorrhage transformation and cause brain injury again.After the time window of thrombolytic therapy,the thrombi cannot be cleared and mechanical thrombectomy is adopted.Usually,after discharge,patients have dyskinesia,speech impairment,visual impairment and so on,which reduce the daily self-care ability of patients and have a great impact on the quality of life of patients.The severity and prognosis of stroke are closely related to the location of intracranial artery occlusion and collateral circulation compensation.In this study,mice were divided into sham operation control group,late operation group for 3 days,late operation group for 7 days and late operation group for 14 days.Three areas of interest were selected:left middle cerebral artery branch(LA),cerebral cortical vein branch(LV)and somatosensory capillary area(LC).Laser specular images were collected before and after middle cerebral artery occlusion model and late opening to analyze the changes of cerebral blood flow in the focal ischemic area.The blood supply from the common carotid artery could not directly supply the middle cerebral artery and its branch blood supply areas.Embolization factors persisted,resulting in microcirculation ischemia and hypoxia and gradually opening of collateral circulation.The reduced level of cerebral perfusion gradually increased three days after surgery.Cortical perfusion was further recovered after recanalization,which was significantly better than that before recanalization,and the recovery effect lasted until 14 days after surgery,which was about 48%of that before surgery.The percentage of infarct area in the 3-day reperfusion group after TTC staining was 21.35%,which was reduced compared with the 7-day reperfusion group and the 14-day reperfusion group,suggesting that early release of the infarct has some significance for the recovery of the infarct area.Cerebral hemodynamic parameters can measure the severity of ischemic infarction,and the perfusion level of ischemic area can evaluate functional remodeling and prognosis recovery.Cortical perfusion of ischemic cerebrovascular disease is of great significance to the prognosis of patients,and is related to the opening of collateral circulation and the establishment of new vessels.After the embolization factor was removed in the three groups with late opening,the cortical perfusion recovery of recanalization was different due to the difference in opening time,and early opening was beneficial to the recovery of cortical perfusion.