兔脑缺血后局部脑血流量和皮质脑电图变化及与氧化型低密度脂蛋白的关系

The effect of oxidized LDL ou rCBF and cortex EEG changes in cholesterol-fed and sugar-fed rabbits during cerebral ischemia

目的研究高胆固醇和高糖饮食对脑缺血后局部脑血流量（ｒＣＢＦ）和皮质脑电图（ＥＥＧ）的影响及与氧化型低密度脂蛋白（ｏｘＬＤＬ）的关系。方法对４９只兔分别给予１％胆固醇、１０％糖水和标准食３种饮食共５周，行颈总动脉结扎或颈内动脉栓塞，同时同点连续记录皮质ＥＥＧ和每３０分钟测１次ｒＣＢＦ，并提取血浆低密度脂蛋白（ＬＤＬ）进行薄层层析（ＴＬＣ）和测定脂质过氧化物（ＬＰＯ）及血脂。结果（１）标准食兔较栓塞组ｒＣＢＦ及皮质ＥＥＧ总能量和平均频率显著降低（Ｐ值＜０．０１），糖水组与标准食组相似；（２）各组皮质ｒＣＢＦ与ＥＥＧ总能量呈显著正相关；（３）胆固醇食兔栓塞组和结扎组缺血侧ｒＣＢＦ及ＥＥＧ均显著降低，血浆和ＬＤＬ中ＬＰＯ含量显著增高，ＬＤＬ的ＴＬＣ分析示有较多Ｘ带形成。结论长期高胆固醇食导致血浆和ＬＤＬ中ＬＰＯ及Ｘ带增多，ｏｘＬＤＬ形成，加速动脉粥样硬化，加重脑缺血时ｒＣＢＦ和ＥＥＧ能量和频率的降低。

Objective The experiments were designed to examine the association of high cholesterol 0and high sugar intake with oxidized low density lipoprotein(oxLDL) and cerebral ischemia.Methods Forty-nine New Zealand rabbits were fed with three different kinds of food, 1% cholesterol,100% sugar water and normal food for five weeks. Cerebral ischemia was induced by ligation or embolization of common carotid artery. rCBF and EEG were recorded simulataneously for 3 hours. Plasma lipid peroxides(LPO) and LDL were measured and the lipid composition of LDL was analyzed with thin layer chromatography(TLC). Results The total power and mean frequency of EEG and rCBF were decreased only in the groups of embolized rabbits fed with normal food or sugar. However, in cholesterol-fed rabbits the total power and mean frequency of rCBF and EEG were significantly decreased both in the ligated and embolized groups and the levels of plasma LPO and LDL were markedly increased. TCL analysis of lipid composition of LDL showed that spot X was higher in cholesterol-fed than that in other groups. Conclusions The results indicated that high cholesterol intake and cerebral ischemia may induce LDL perioxidization which may lead to rCBF and EEG changes during cerebral ischemia.