Dynamic Detection of Thrombolysis in Embolic Stroke Rats by Synchrotron Radiation Angiography

A rodent model of embolic middle cerebral artery occlusion is used to mimic cerebral embolism in clinical patients. Thrombolytic therapy is the effective treatment for this ischemic injury. However, it is difficult to detect thrombolysis dynamically in living animals. Synchrotron radiation angiography may provide a novel approach to directly monitor the thrombolytic process and assess collateral circulation after embolic stroke. Thirty-six adult Sprague-Dawley rats underwent the embolic stroke model procedure and were then treated with tissue plasminogen activator. The angiographic images were obtained in vivo by synchrotron radiation angiography. Synchrotron radiation angiography confirmed the successful establishment of occlusion and detected the thrombolysis process after the thrombolytic treatment. The time of thrombolytic recanalization was unstable during embolic stroke. The infarct volume increased as the recanalization time was delayed from 2 to 6 h (p < 0.05). The collateral circulation of the internal carotid artery to the ophthalmic artery, the olfactory artery to the ophthalmic artery, and the posterior cerebral artery to the middle cerebral artery opened after embolic stroke and manifested different opening rates (59%, 24%, and 75%, respectively) in the rats. The opening of the collateral circulation from the posterior cerebral artery to the middle cerebral artery alleviated infarction in rats with successful thrombolysis (p < 0.05). The cerebral vessels of the circle of Willis narrowed after thrombolysis (p < 0.05). Synchrotron radiation angiography provided a unique tool to dynamically detect and assess the thrombolysis process and the collateral circulation during thrombolytic therapy.