Establishment and evaluation of the model of middle cerebral artery occlusion reperfusion in mice / 中国组织工程研究

ABSTRACT

BACKGROUND: Most animal experiments of transgene are derived from mice; therefore, it is necessary to establish a focal cerebral ischemiareperfusion model and significant to prevent and cure ischemic cerebrovascular diseases.OBJECTIVE: To establish a convenient and reliable model with middle cerebral artery occlusion reperfusion (MCAO/R) in mice.DESIGN: Randomized controlled animal study.SETTING: Institute of Cerebrovascular disease, Affiliated Hospital of Medical College of Qingdao University.MATERIALS: Twenty healthy BALB/c mice, of both genders, weighing 25-30 g, of SPF grade, were divided into sham operation group (n=5), ischemia group (n=10) and 22-hour reperfusion group (n=5) on the basis of digital table. In addition, according to digital table, 130 healthy male Kunming mice were divided into sham operation group (n=10), 24-hour ischemia group (n=30), 2-hour ischemia/22-hour, 46-hour and 70-hour reperfusion groups with 30 in each group; meanwhile, 30 female mice were divided into sham operation group, 24-hour ischemia group and 2-hour ischemia/22-hour reperfusion group with 10 in each group. All Kunming mice were weighing 25-30 g and of SPF grade.METHODS: The experiment was carried out in the Institute of Cerebrovascular Disease, Affiliated Hospital of Medical College of Qingdao University from July 2005 to March 2006. The 6-0 suture with silica gel covered at an end was sent from the left external carotid artery (ECA) into internal carotid artery (ICA) till arriving at the initiation of middle cerebral artery (MCA) to block the blood stream in it, then drawing the suture from ICA 2 hours after occlusion to accomplish reperfusion. Mice were cut off their heads in sham operation group at 24 hours after operation, in ischemia group at 24 hours after blocking blood stream and in reperfusion group at 24, 48 and 72 hours after operation. Reliability of models was evaluated with neurology score and tetrazolium chloride stain. Longa standard scores: neurology score ≥ 1 point was regarded as successful models;coronal sections of brain tissue were stained with tetrazolium chloride, and the white region was regarded as infarcted volume.MAIN OUTCOME MEASURES: Neurology score and infarcted volume after staining of triphenyltetrazolium chloride in brain tissue.RESULTS: All mice were involved in the final analysis. ① Successful rate was 20% of BALB/c mice, 66.7%-73.3% of male Kunming mice and 40%-50% of female Kunming mice. ② Brain sections of BALB/c mice in sham operation group were orange at both sides of cortex and infarction focus was not observed. A big infarcted volume was observed on brain sections of mice in ischemia group, and infarcted volume counted for 50%-70% as homonymy hemisphere on optochiasmatic coronal sections. The condition of Kunming mice was similar to that of BALB/c mice, but infarcted volume counted for 40%-65%. In addition, condition in ischemiareperfusion group was similar to that in ischemia group. A big infarcted volume was observed on brain sections, and infarcted volume counted for 50%-75% as homonymy hemisphere on optochiasmatic coronal sections.The condition of Kunming mice was similar to that of BALB/c mice, but infarcted volume counted for 40%-65%.CONCLUSION: The model with MCAO/R in mice characterizes by relatively smaller trauma, and the ischemic region is stable; therefore, it can be used to accurate timing control of ischemia/reperfusion. This model is an ideal one for researching pathophysiological changes, prognosis and therapy in cerebrovascular disease.