慢性前脑缺血致痴呆大鼠脑血流量及行为学对比研究

Study on cerebral blood flow and behavior in chronic forebrain ischemia inducing vascular dementia rats

目的研究脑血流量在慢性前脑缺血致血管性痴呆(VD)发病机制中的作用。方法采用双侧颈总动脉永久结扎方法制备慢性前脑缺血动物模型;应用激光多普勒血流仪检测各组大鼠术后不同时间点(术后24h、1w、0.5、1、2、3、4个月)额叶、顶叶、海马及皮质下区局部脑血流量(rCBF);利用Morris水迷宫方法检测各组大鼠记忆功能。结果大鼠双侧颈总动脉永久结扎后额叶、顶叶、海马及皮质下区的rCBF明显下降,以术后24小时最明显,至4个月时仍明显低于正常,呈慢性持续性下降的趋势;各实验组大鼠从术后1个月开始即出现明显的记忆功能障碍,至4个月时记忆功能障碍持续存在。结论双侧颈总动脉永久结扎可导致大鼠出现慢性持续性脑血流量下降;慢性持续性脑血流量下降可导致大鼠出现持续性认知功能障碍。

Objective To study the role of cerebral blood flow （rCBF） on the pathogenesis of chronic forebrain ischemia inducing vascular dementia （VD）. Methods Chronic forebrain ischemia model was made by permanent occlusion of bilateral carotid arteries. The cognitive function of the rats were estimated by Morris water maze test and rCBF in prefrontal cortex, parietal cortex, hippoeampus and subcortex was assessed by laser doppler flowmetry on any different timepoint after operation （24 h, 7, 14 d, 1,2, 3, 4 mon）. Results rCBF in prefrontal cortex, parietal cortex, hippocampus and subcortex obviously decreased, especially on 24 h post operation, and was lower than that of normal group on 4 mon post operation obviously, rCBF showed a tendency to decline. The cognitive functions of rats were obviously reduced after 1 mon of the chronic cerebral hypoperfusion and lasted until 4 mon. Conclusions The reduction of rCBF might be induced by permanent occlusion of bilateral carotid arteries, which can result in persistent impairment of the cognition function.