Uncoupling effect of mercuric chloride on mitochondria isolated from an hepatic cell line

• Published in: Journal of applied toxicology Vol. 21; no. 4; pp. 323 - 329
• Main Authors: Königsberg, Mina, López-Díazguerrero, Norma Edith, Bucio, Leticia, Gutiérrez-Ruiz, María Concepción
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-07-2001; Wiley
• Subjects: Adenosine Diphosphate - metabolism; Adenosine Triphosphatases - metabolism; Biological and medical sciences; Cell Line; Cell Survival - drug effects; Cells, Cultured; Chemical and industrial products toxicology. Toxic occupational diseases; dithiothreitol; Dithiothreitol - pharmacology; Electron Transport - drug effects; Enzyme Inhibitors - pharmacology; Humans; Medical sciences; mercuric chloride; Mercuric Chloride - pharmacokinetics; Mercuric Chloride - toxicity; Mercury - metabolism; mercury toxicity; Metals and various inorganic compounds; Microscopy, Electron; mitochondria; Mitochondria, Liver - drug effects; Mitochondria, Liver - metabolism; Mitochondria, Liver - ultrastructure; oligomycin; Oligomycins - pharmacology; Oxygen Consumption - drug effects; Potassium Cyanide - pharmacology; respiration; respiratory chain; Rotenone - pharmacology; Subcellular Fractions - metabolism; Toxicology; Uncoupling Agents - pharmacokinetics; Uncoupling Agents - toxicity; WRL-68; Human; Prevention; Oxidative stress; Mitochondria; Cell line; Toxicity; Liver; In vitro; Mercury Chlorides; Heavy metal; Cell respiration
• ISSN: 0260-437X; 1099-1263
• DOI: 10.1002/jat.763

A human fetal hepatic cell line (WRL‐68) was used as a model to study the damage produced by mercury. The Hg(II) uptake by WRL‐68 cells was found to be in a biphasic manner with a rapid initial uptake phase lasting about 5 min, followed by a sustained phase of slower accumulation. Distribution of mercury was studied and mitochondria were found to be the major target for mercury in this cell line (48%), followed by nuclei (38%), cytosol (8%) and microsomes (7%). Mitochondrial morphological damage after mercury treatment was observed by transmission electron microscopy. To determine if the toxic effect of mercury on mitochondrial bioenergetics was direct or indirect, mitochondria were isolated from WRL‐68 cells after 1 h of pre‐incubation with 0.5 µM HgCl2. Oxygen consumption was quantified in two sets of experiments: in the presence of classical mitochondrial respiratory inhibitors; and in the presence of oligomycin. No significant difference was found in respiration with classical inhibitors, indicating that mercury does not affect directly the mitochondrial respiratory chain. However, mitochondria of Hg‐treated cells were not inhibited when oligomycin was added, probably due to an uncoupling effect. This effect was prevented with dithiothreitol (DTT) treatment. A possible explanation for mercury's effect on mitochondria and its relation with oxidative stress is presented. Copyright © 2001 John Wiley & Sons, Ltd.