Uptake, cellular distribution and DNA damage produced by mercuric chloridein a human fetal hepatic cell line

A human hepatic cell line (WRL-68 cells) was employed to investigate the up take of the toxic heavy metal mercury. Hg accumulation in WRL-68 cells is a time and concentration dependent process. A rapid initial phase of uptake was followed by a second slower phase. The transport does not require energ y and at low HgCl2 concentrations (< 50 mu M) Hg transport occurs by temper ature-insensitive processes. Subcellular distribution of Hg was: 48% in mit ochondria, 38% in nucleus and only 8% in cytosolic fraction and 7% in micro somes. Little is known at the molecular level concerning the genotoxic effe cts following the acute exposure of eucaryotic cells to low concentrations of Hg. Our results showed that Hg induced DNA single-strand breaks or alkal i labile sites using the single-cell gel electrophoresis assay (Comet assay ). The percentage of damaged nucleus and the average length of DNA migratio n increased as metal concentration and time exposure increased. Lipid perox idation, determined as malondialdehyde production in the presence of thioba rbituric acid, followed the same tendency, increased as HgCl2 concentration and time of exposure increased. DNA damage recovery took 8 h after partial metal removed with PBS-EGTA. (C) 1999 Elsevier Science B.V. All rights res erved.