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采用能谱法研究铅对大鼠血脑屏障的通透性 |
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阮素云 顾祖维 杨勇骥
【摘要】 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30 mg/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10 mg/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30 mg/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。
【关键词】 铅 血脑屏障
Energy Dispersive X-ray Analysis in Studying the Permeability of Blood-Brain Barrier Caused by Lead in Rats RUAN Suyun*, GU Zuwei, YANG Yongji. *Shanghai Municipal Institute for Occupational Health, Shanghai 200003
【Abstract】 Objective To observe the changes in permeability of blood-brain barrier caused by lead in rats. Methods Rats were fed with drinking water containing 10 and 30 mg/L of lead for three months. Electron microscopy lanthanum nitrate-tracing and electron probe-energy dispersive X-ray (EDX) analysis were used to observe the distribution of lead in different cells of bilateral sides of capillaries of cerebral cortex and the changes in their permeability. Results There was significant difference in blood lead levels between the rats with drinking water of 10 mg/L lead and the controls, but only a peak of lead, Lα, could appear in plasmalemma of endotheliaocyte endosurface in capillaries, and no any peak in the basement membrane of endotheliocyte of the outer-side, end feet of astrocytes and axons of neurons. Lanthanum nitrate-tracing showed changes in capillary permeability. But, in those with drinking water of 30 mg/L of lead, peak of lead, Lα and Mα could appear in all cells mentioned above. Meanwhile, lanthanum salt granules, which penetrated the cellular gaps of endothelia and seeped in the basement and its peripheral cells, could be found in certain sites of the capillaries with larger diameters. Conclusion It [1] [2] 下一页
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