Lachapelle M, Guertin F, Marion M, Fournier M, Denizeau F
Département des sciences biologiques and TOXEN, Université du Québec à Montréal, Canada.
J Toxicol Environ Health. 1993 Apr;38(4):343-54. doi: 10.1080/15287399109531723.
The toxicity of mercury on hepatocytes was studied at the ultrastructural, biochemical, and immunocytochemical levels. Albumin metabolism was examined because it is a representative liver-specific function. A novel cytochemical method using the protein A-gold technique for the in situ localization of albumin in hepatocyte cultures was applied. Primary rat hepatocyte cultures were exposed to increasing HgCl2 concentrations. Cytotoxicity was assessed by measuring the release of lactic dehydrogenase from the cells. At the highest exposure concentration tested (50 microM), Hg was found to be significantly cytotoxic in contrast to what occurred at 5.0 and 0.5 microM. The level of albumin secreted, as measured by ELISA, was decreased by approximately 38% at 5.0 microM HgCl2 and was found not to be different from that of controls at lower concentrations. The ultrastructural analysis showed that hepatocytes treated with 5.0 microM HgCl2 undergo drastic morphological changes such as a decreased number of ribosomes associated with the rough endoplasmic reticulum, and the disappearance of the latter organelle, proliferation of the smooth endoplasmic reticulum, and dilatation of both the Golgi apparatus and the biliary canaliculus-like structures. Immunocytochemical detection of albumin-immunoreactive sites using protein A-gold labeling further revealed that these were less abundant in hepatocytes treated with 5.0 microM HgCl2 (-64%) as compared to control preparations. These results suggest that one of the effects of mercury on hepatocytes is to affect liver-specific functions such as albumin production, possibly through interference with ribosomal function. This study also demonstrates for the first time the applicability of the high-resolution protein A-gold technique for toxicological investigations on hepatocytes in vitro.
在超微结构、生化和免疫细胞化学水平上研究了汞对肝细胞的毒性。由于白蛋白代谢是一种典型的肝脏特异性功能，因此对其进行了检测。应用了一种使用蛋白A-金技术在肝细胞培养物中对白蛋白进行原位定位的新型细胞化学方法。将原代大鼠肝细胞培养物暴露于浓度不断增加的氯化汞中。通过测量细胞中乳酸脱氢酶的释放来评估细胞毒性。在所测试的最高暴露浓度（50微摩尔）下，与5.0和0.5微摩尔时的情况相比，汞具有明显的细胞毒性。通过酶联免疫吸附测定法测量，在5.0微摩尔氯化汞时分泌的白蛋白水平下降了约38%，并且发现在较低浓度下与对照组没有差异。超微结构分析表明，用5.0微摩尔氯化汞处理的肝细胞发生了剧烈的形态变化，如与粗面内质网相关的核糖体数量减少，后者细胞器消失，滑面内质网增殖，以及高尔基体和胆小管样结构扩张。使用蛋白A-金标记对白蛋白免疫反应位点进行免疫细胞化学检测进一步表明，与对照制剂相比，在5.0微摩尔氯化汞处理的肝细胞中这些位点较少（-64%）。这些结果表明，汞对肝细胞的作用之一是影响肝脏特异性功能，如白蛋白产生，可能是通过干扰核糖体功能。本研究还首次证明了高分辨率蛋白A-金技术在体外肝细胞毒理学研究中的适用性。
