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目的研究铅从血液进入脑实质的可能机制，血管内皮细胞的连续层对铅的屏障作用。方法用电镜硝酸镧示踪和电子探针能量色散Ｘ射线分析观察大鼠饮用含铅水（１０和３０ｍｇ／Ｌ）３个月后，铅在大鼠脑皮质区毛细血管内、外侧不同细胞中的分布与血脑屏障通透性的变化。结果对照组与１０ｍｇ／Ｌ组血铅浓度虽有差异，但在毛细血管内皮细胞内表面的质膜中都只收集到了铅的Ｌα峰，在内皮细胞外侧的基膜，星形胶质细胞足板及神经细胞轴突中未出现任何铅峰，同时硝酸镧示踪也未显示血管通透性有变化。而在３０ｍｇ／Ｌ组，上述细胞部位均收集到了铅的Ｌα峰和Ｍα峰，同时在管腔较大的毛细血管的某些部位可见镧盐颗粒穿过内皮细胞间的缝隙到达基膜及周细胞。结论血管内皮细胞内表面的质膜是铅作用于脑的最初靶点，血管内皮细胞的连续层对铅有屏障作用，但该屏障作用非常弱，铅在内皮细胞内表面的质膜中积累稍多，便会损害内皮细胞间的紧密联结透至脑实质，与硝酸镧示踪的结果一致。
Objective To investigate the possible mechanism by which lead enters the parenchyma of the brain and the protective effect of successive layers of vascular endothelial cells on lead. Methods Electron microscope Lanthanum nitrate tracing and electron probe energy dispersive X-ray analysis were used to observe the lead drinking water (10 and 30 mg / L) in rats for 3 months. Lead in the rat cerebral cortex area capillary inner and outer cells In the distribution of blood-brain barrier permeability changes. Results Although there was a difference in blood lead levels between the control group and the 10 mg / L group, only lead Lα peak was collected in the plasma membrane on the inner surface of capillary endothelial cells. In the basal membrane outside the endothelial cells, astrocyte There was no lead peak in the axons of the plate and nerve cells, and lanthanum nitrate tracing did not show any change in vascular permeability either. In 30mg / L group, the Lα peak and Mα peak of Pb were all collected in the above-mentioned cell sites. At the same time, in some parts of the capillary with larger lumen, lanthanum salt particles penetrated the gap between endothelial cells and reached the basement membrane cell. CONCLUSIONS: The plasma membrane on the inner surface of vascular endothelial cells is the primary target of lead in the brain. Continuous layers of vascular endothelial cells have a barrier effect on lead, but the barrier is very weak. Lead accumulates slightly in the plasma membrane of the inner surface of endothelial cells More, it will damage the tight junction between endothelial cells penetrate into the brain parenchyma, consistent with the results of lanthanum nitrate tracing.