脑缺血预处理降低大鼠脑一氧化氮水平抗脑缺血损伤的实验研究

目的:探讨脑缺血预处理对大鼠缺血性脑损伤的保护作用及其与一氧化氮(NO)的关系。方法:缺血预处理组大鼠钳夹阻断两侧颈总动脉15min;3天后,线栓法制作大脑中动脉阻塞模型,线栓阻塞右大脑中动脉8h。非缺血预处理组除不钳夹阻断两侧颈总动脉外,其余步骤相同。右大脑中动脉阻塞8h后,对大鼠进行神经功能缺失评分及亚硝酸盐还原法测定大脑皮层及海马的NO含量。结果:(1)缺血预处理组大鼠神经功能缺失评分较非缺血预处理组有显著改善(P＜0．01);(2)缺血预处理组大鼠缺血侧和自身对照侧皮层、海马的NO含量较非缺血预处理组大鼠明显下降(P＜0．05)。结论:大鼠脑缺血预处理对随后的脑缺血损伤具有保护作用,其机制之一可能是降低了脑组织的NO水平。

The study about cerebral ischemic preconditioning against cerebral ischemic injury by lowing the cerebral content of nitric oxide in rat

Objective:To assess the protective effect of cerebral ischemic preconditioning and the link between the pro- tective effect and nitric oxide (NO) in cerebral ischemic injury of rat.Methods:Ischemic preconditioning group rats were produced by clamping the bilateral common carotid arteries (BCCA) to occlude blood flow for 15 minutes.Following re- covery for 3 days,the middle cerebral artery occlusion (MCAO) models of rats were made by using a thread to occlude the right middle cerebral artery for 8 hours.The non-ischemic preconditioning group rats were suffered the same proce- dures except the BCCA were not clamped.Then the neurologic function wane of rats was estimated and the content of NO in cortex and hippocampus were measured by nitrite reduction.Results:(1)The neurologic disorders of the ischemic pre- conditioning group rats were less severe significantly than those of the non-ischemic preconditioning group rats (P＜0. 01).(2)The content of NO in cerebral cortex and hippocampus of the ischemic and self-control side of ischemic precondi- tioning group rats were less significantly than those of the non-ischemic preconditioning group rats (P＜0.05).Conclu- sions:Cerebral ischemic preconditioning hasprotection against the sequent cerebral ischemic injury of rat.The one of the neuroprotectivemechanisms of cerebral ischemic preconditioning maybe by reducing the content of NO in cerebraltissue of rat.