Novel Rat Model of Embolic Cerebral Ischemia Using a Radiopaque Blood Clot and a Microcatheter Under Fluoroscopy

Conventional rat models of thromboembolic stroke do not allow control of infarct size or spontaneous recanalization. We aimed to develop a novel rat thromboembolic stroke model that ensures highly reproducible infarct sizes and locations within the MCA territory and does not require arterial ligation. Twenty male Sprague-Dawley rats and two sham-operated rats were included. A microcatheter was navigated from the caudal ventral artery to the internal carotid artery using digital subtraction angiography. A blood clot (diameter, 0.86 mm; length, 3 mm) containing zirconium dioxide was advanced in the catheter. Fluoroscopy was performed at 1, 3, 6, and 24 h after stroke model creation, and TTC staining was conducted at 24 h. Neurological deficit scores were measured. In all embolized rats, the ACA and MCA bifurcation were selective. Median operating time was 6 min. The position of the radiopaque blood clot remained unchanged for 24 h after model creation in 19/20 rats. Median infarct volume was 242 mm³ (IQR, 239-262 mm³). We present a novel rat model of highly reproducible focal infarct in only the MCA territory. Fluoroscopy effectively identified any blood clot migration. This model could contribute to the development of new thrombolytic agents.