慢性低灌注大鼠影像与病理对照研究

Study on imaging and pathology of rats with chronic cerebral hypoperfusion

目的观察慢性低灌注大鼠影像学特征,确定头颅MRI特征、海马的容积测量与相对应的组织病理学改变之间的关系。方法雄性Wistar大鼠60只,随机分为缺血组(30只)和假手术组(30只)。利用Morris水迷宫方法检测术后1、2、3、4、5个月大鼠的记忆功能;分别行头颅MRI检查与海马容积测量,通过HE染色,光镜观察大鼠海马CA1区神经细胞的形态学变化。结果与假手术组比较,缺血组大鼠记忆功能障碍在造模后2个月即出现,逃避潜伏期明显延长,穿越平台次数明显减少(P<0.01)。缺血1个月时海马CA1区可见神经元减少。双侧颈总动脉结扎术后3个月头颅MRI显示,长期慢性脑缺血后海马体积缩小。结论慢性低灌注大鼠认知功能降低,可能与海马缺血损害有关。海马的影像学改变相对滞后于病理改变。

Objective To observe the imaging features of rats with chronic cerebral hypoperfusion, and to investigate the relations between cranial MRI features, volume of hippocampus and histological changes. Methods Sixty male Wistar rats were randomly divided into sham operation group and ischemia group of 30 rats each. Morris water maze test was performed at 1,2,3,4,5 months after the operation. Examinations including MRI, MR volumetric analysis of hippocampus and neural pathologic examination（including HE） were undertaken on both groups at different time points after operation to observe the morphological changes of nerve cells in hippocampus CA1 area in each group. Results At 2 month after operation,compared with the sham operation group,the rats in the isehemie group demonstrated memory impairment on Morris water maze test, extension of escape latency and reduction of the number of crossing the platform significantly （P 〈 0. 01）. At 1 month after set up of ischemic model,neurons in hippocampal CA1 area reduced. Cranial MRI showed that the volume of hippocampus reduced in rats at the time of 3 months after ligating bilateral common carotid arteries. Conclusion Cognitive dysfunction of rats with cerebral hypoperfusion may be associated with ischemic damage to the hippocampus. The changes in imaging of the hippocampus relatively lag behind the pathological changes.