Canine model of ischemic stroke with autologous thrombus in three dogs; Magnetic resonance imaging features and histopathological findings

초록

Ischemic stroke is the most common type of stroke in humans. The purpose of this study was to evaluate the di- agnostic value of magnetic resonance imaging (MRI) in a canine model of stroke. Ischemic stroke was induced by us- ing prepared autologous thrombus. The dogs were placed in lateral recumbency on the operation table and the cervical area of each dog was sterilized by using alcohol. After mak- ing a cervical incision, the common carotid artery and inter- nal carotid artery (a branch of the common carotid artery that supplies an anterior part of the brain) were exposed. A 200 µL injection of the autologous thrombus prepared 24 hr prior to surgery was delivered with a 20 gauge venous catheter through an internal carotid artery. After successful delivery of the autologous thrombus, the venous catheter was removed, and the cervical incision was sutured. Neuro- logic signs including generalized seizures, tetraparesis, and altered mental status, were observed in all 3 dogs after in- duction of ischemic stroke and the signs manifested immedi- ately after awakening from anesthesia. T1- and T2-weighted images and fluid-attenuated inversion recovery (FLAIR) images of the brain were acquired 1 day before and 1 day after surgery. On the day following ischemic stroke induc- tion, MRI revealed multifocal lesions in the cerebral cortex and subcortex such as T1 hypointensity, T2 hyperintensity, FLAIR hyperintensity, and diffusion-weighted hyperinten- sity in all 3 dogs. Upon postmortem examination, ischemic lesions were found to be consistent with the MRI findings and they were unstained with 2% triphenyltetrazolium chloride. Histologic features of the earliest neuronal changes such as cytoplasmic eosinophilia with pyknotic nuclei were identified. Neuropil spongiosis and perivascular cuffing were also prominently observed at the infarcted area. The present study demonstrated the features of MRI and histo- pathologic findings in canine ischemic stroke models.

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