大白鼠脑中表达低密度脂蛋白(LDL)受体的神经元可吸收含脱辅基蛋白E(ApoE)的脂蛋白

用组织荧光和免疫细胞化学相结合法研究含脱辅基蛋白E(ApoE)的脂蛋白是否可被中枢神经元所吸收。实验结果如下: 1.含ApoE的脂蛋白仅被注射针迹附近的神经元所吸收。 2.只有表达出低密度脂蛋白(LDL)受体的神经元才能吸收含ApoE的脂蛋白。 3.不能表达LDL受体的神经元不能吸收含ApoE的脂蛋白。 实验结果表明,含ApoE的脂蛋白、LDL受体的表达及ApoE-LDL受体的相互作用是哺乳动物中枢神经系统内实现胆固醇运输和维持胆固醇代谢平衡的重要机制。

UPTAKE OF APOLIPOPROTEIN E-CONTAINIG LIPOPROTEINS BY NEURONS OF THE RAT BRAIN THAT EXPRESS LOW DENSITY LIPOPROTEIN RECEPTORS

In this study, we used fluorescence histological technique in combination with immunocytochemical method to investigate if ApoE-containing lipoprotein can be taken up by neurons of central nervous system in mammals. The results from these experiments are as follows.1. The uptake of labeled ApoE-containing lipoproteins was observed only in neurons distributed along the track of injection.2. The labeled ApoE-containing lipoproteins were internalized by neurons that expressed low density lipoprotein (LDL) receptors.3. Neurons that did not express LDL receptors did not lake up labeled ApoE-containing lipoproteins.Conclusions. Neurons that express LDL receptors have the ability to bind and internalize ApoE-containing lipoproteins present in their environment. This suggests that ApoE-containing lipoproteins and the regulated expression of LDL receptors provide a mechanism for cholesterol transfer and homeostasis within the central nervous system of the mamals.