Morrison D G, Medina D
Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.
Toxicol Lett. 1988 Dec;44(3):307-14. doi: 10.1016/0378-4274(88)90170-1.
Previous studies have demonstrated that selenite exerts a reversible and non-lethal inhibition of cell growth which could be correlated with a 58 K selenoprotein. Prolonged exposure to 5 microM selenite is cytotoxic. This cytotoxic effect is heralded by the cells floating off the dish. These floating cells contained over a log more selenite than did the attached cells. The floating cells also had a higher total amount per cell of covalently incorporated selenite in the form of volatile selenides. No specific selenoprotein could be correlated with the cytotoxic effect of selenite. However, a greater aggregation of selenoproteins was observed in dead vs. viable cells. This change probably was a late manifestation of cell death, whereas the increased amount of volatile selenides marked the early stages of acute selenosis and cell death. The results suggest that the cellular response to selenite exposure contains two phases: an early reversible inhibition of cell growth, and a late irreversible cytotoxic effect. The former is characterized by an increase in a 58 K selenoprotein, whereas the latter by an increase in volatile selenides. The results suggest that experiments evaluating specific effects of selenite exposure on biochemical function need to distinguish between the two phases of cell response.
先前的研究表明，亚硒酸盐对细胞生长具有可逆且非致死性的抑制作用，这可能与一种58K的硒蛋白有关。长时间暴露于5微摩尔的亚硒酸盐会产生细胞毒性。这种细胞毒性作用的先兆是细胞从培养皿上脱落。这些漂浮的细胞所含的亚硒酸盐比贴壁细胞多一个对数以上。漂浮细胞中以挥发性硒化物形式共价结合的亚硒酸盐总量也更高。没有特定的硒蛋白与亚硒酸盐的细胞毒性作用相关。然而，在死细胞与活细胞中观察到硒蛋白有更大程度的聚集。这种变化可能是细胞死亡的晚期表现，而挥发性硒化物数量的增加则标志着急性硒中毒和细胞死亡的早期阶段。结果表明，细胞对亚硒酸盐暴露的反应包含两个阶段：早期对细胞生长的可逆抑制，以及晚期不可逆的细胞毒性作用。前者的特征是一种58K硒蛋白增加，而后者的特征是挥发性硒化物增加。结果表明，评估亚硒酸盐暴露对生化功能的特定影响的实验需要区分细胞反应的两个阶段。
