Russo M A, Kapoor S C, van Rossum G D
Department of Experimental Medicine, Universita La Sapienza, Rome, Italy.
Br J Exp Pathol. 1988 Apr;69(2):221-34.
The subcellular distribution and ultrastructural effects of lead have been studied in the kidneys and liver of rats given lead acetate (600 ppm Pb2+) in their drinking water for 6 months. Control rats were given sodium acetate. Tissue samples were fixed in glutaraldehyde and examined by electron microscopy with and without staining. Unstained sections of both kidney and liver from lead-treated animals showed small particles (2-5 nm diameter) of very high electron density which appear to represent a deposited form of Pb2+. Ultrastructural changes in the kidneys were largely confined to glomeruli (swelling of endothelial cells, fusion of foot processes, thickening of basement membrane) and proximal tubules (ranging from minimal sub-lethal changes to necrotic disorganization). The electron-dense particles of Pb2+ occurred in large clusters in basement membranes. As individual particles, or small groups, they were numerous in nuclei of proximal epithelium but usually only a few, largely confined to vesicles or inclusion bodies, were present in the cytoplasm. Only when cells were markedly damaged morphologically were particles more generally distributed in the cytoplasm. Liver damage by Pb2+ was largely confined to centrilobular regions. Endothelial and Kupffer cells were the most affected; they often sequestered large numbers of the particles. In parenchymal cells, particles were few and mainly in vesicles, but they were more widely distributed in the cytoplasm when morphological injury was apparent. The free distribution of Pb2+ in liver and kidney seems to be limited by its deposition in basement membranes and sequestration in reticulo-endothelial cells; intracellular distribution in healthy cells is also limited, by deposition in nuclei (in kidney only) or cytoplasmic vesicles.
研究了给大鼠饮用含醋酸铅（600 ppm Pb2+）的水6个月后，铅在大鼠肾脏和肝脏中的亚细胞分布及超微结构效应。对照组大鼠饮用醋酸钠。将组织样本用戊二醛固定，并通过电子显微镜进行有无染色检查。来自铅处理动物的肾脏和肝脏的未染色切片显示出直径为2 - 5纳米的非常高电子密度的小颗粒，这些颗粒似乎代表了Pb2+的沉积形式。肾脏的超微结构变化主要局限于肾小球（内皮细胞肿胀、足突融合、基底膜增厚）和近端小管（从最小的亚致死性变化到坏死性紊乱）。Pb2+的电子致密颗粒大量聚集在基底膜中。作为单个颗粒或小群体，它们在近端上皮细胞核中数量众多，但在细胞质中通常只有少数，主要局限于囊泡或包涵体中。只有当细胞在形态上明显受损时，颗粒才更普遍地分布在细胞质中。Pb2+对肝脏的损伤主要局限于小叶中心区域。内皮细胞和库普弗细胞受影响最大；它们常常螯合大量颗粒。在实质细胞中，颗粒很少，主要存在于囊泡中，但当形态学损伤明显时，它们在细胞质中的分布更广泛。肝脏和肾脏中Pb2+的自由分布似乎受到其在基底膜中的沉积以及在网状内皮细胞中的螯合的限制；在健康细胞中的细胞内分布也受到限制，表现为在细胞核中沉积（仅在肾脏中）或细胞质囊泡中沉积。
