A new model of cerebral ischemia in mice

Background Based on the commonly used local cerebral ischemia models, such as clot embolization, photochemically induced thrombosis and sludged blood embolization, a new model of local cerebral ischemia in mice was popularized. Methods The model of distal middle cerebral artery occlusion (dMCAO) was prepared by permanently blocking the distal middle cerebral artery (MCA) of mice. Cerebral blood flow (CBF) was monitored by real-time laser speckle contrast imaging system. Triphenyltetrazolium chloride (TTC) staining and HE staining were used to detect ischemic infarcts. Clark classification was used to evaluate neurological function. Results Laser speckle contrast imaging system showed CBF decreased significantly after ablation of MCA by electrocoagulation. TTC staining showed that the ischemic region was only located in cerebral cortex, and no obvious damage was found in subependymal basal ganglia and hippocampus. HE staining showed that most nerve cells died in the ischemic region, and there was obvious cell density around the ischemic region, which was considered to be inflammatory cells and various nerve cells. One, 3, 7 and 14 d after model preparation, the mice weighed 22, 20.70, 19.50 and 20.10 g, respectively. Body symmetry scores in Clark classification were 0.75, 0.75, 0.50 and 0.50, respectively; gait scores were 0, climbing scores were 0, turning test scores were 0.50, 0.75, 0.50 and 0.25, forearm symmetry scores were 0.25, forced turning scores were 0, beard reactivity scores were 1, 1, 1 and 0.50 respectively. Conclusions The improved new model of dMCAO can simulate local cerebral ischemia with minor neurological defect, and can be used as an experimental model to study the pathophysiological changes and repair process of the vessels after nerve injury as well as the nerve cells involved in the repair process after nerve injury. DOI: 10.3969/j.issn.1672-6731.2018.12.008