大鼠慢性前脑缺血解除后脑过度灌注模型的建立

Modelling of cerebral hyper-perfusion after chronic forebrain ischemia in rats

目的建立大鼠慢性前脑缺血基础上的脑过度灌注模型。方法选取雄性Wistar大鼠72只依随机数字表均分为两个模型建造组。缺血模型采用双侧颈总动脉结扎，随机数字表分为空白对照、假手术组、缺血2周组、缺血4周组，每组9只，结扎前后分别测定脑额叶血流、比较各组行为学评分、脑梗死面积。过度灌注模型是在缺血模型基础上，再灌注同时经尾静脉持续输注去氧肾上腺素4μg·kg^-1·min^-1，使再灌注后脑额叶血流超过基础值的200％。随机分为空白对照组、盐水组、过度灌注0．5h组、过度灌注2h组，每组9只，再灌注前后分别测定脑额叶血流，比较各组行为学评分、血脑屏障通透性、脑干湿重比值。结果大鼠双侧颈动脉结扎后前脑血流减少可达67％4-2％，脑过度灌注组与盐水输注组的脑血流变化值差异有统计学意义（P〈0．01）。缺血2周组的神经功能评分、脑梗死面积与正常对照组差异无统计学意义，缺血4周组的脑梗死面积与正常对照组差异有统计学意义。脑过度灌注2h组的血脑屏障通透性改变有统计学意义（P〈0．05）。结论结扎大鼠双侧颈总动脉2周后脑过度灌注2h可较好地建立大鼠脑过度灌注综合征模型。

Objective To establish the cerebral hyper-perfusion model after chronic forebrain isehemia in rats. Methods A total of 72 male rats were equally randomized into 2 modeling groups. The ligation of bilateral common carotid artery could induce chronic forebrain isehemia. And 36 rats were randomly grouped by ischemia duration ： control group （ n = 9 ） , sham group （ n = 9 ） , 2-week ischemia group （n =9） and 4-week ischemia group （n =9）. The blood flow in frontal lobe was measured at pre- and post-ligation. The neurological score and cerebral infarction area were also compared among the groups. The cerebral reperfusion was concurrently undertaken with an infusion dose of phenylephedrine at 4 μg · kg^-1 · min^-1 via tail vein to produce cerebrally hyperperfused blood flow rate over 200% of baseline following chronic isehemia. According to cerebral hyper-perfusion duration, 36 rats were randomly assigned into 4 groups ： control group （ n = 9 ）, saline infusion group （ n = 9 ）, 30-minute cerebral hyper-perfusion group （ n = 9） and 2-hour cerebral hyper-perfusion group （ n = 9 ）. The blood flow in frontal lobe was measured before and after cerebral hyper-perfusion. The neurological score, blood-brain barrier permeability and dry- wet weight ratio of brain also were compared among the groups. Results The forebrain blood flow decreased by 67% ：t：2% after the ligation of bilateral common carotid artery. There was significant difference between cerebral hyper-perfusion and saline infusion groups （ P 〈 0. 01 ）. No statistic difference was observed in neurological score and cerebral infarction area between 2-week isehemia and control groups. But it was obvious between 4-week ischemia and control groups. The permeability in blood-brain barrier of rats significantly increased in 2-hour hyper-perfusion group （ P 〈 0. 05 ）. Conclusion The 2-hour duration of cerebral hyper-perfusion following a 2-week ligation of bilateral common carotid artery may establish a reliable cerebral hyper-perfusion model in rats.