ABSTRACT
Nickel, cobalt and chromium can induce allergic contact dermatitis (ACD) and may provoke irritant reactions in the skin. This study aimed at investigating cytotoxicity and cell viability along with intracellular metal accumulation in HaCaT human keratinocytes exposed to soluble forms of nickel, cobalt or chromium. The EC50 (24 h) values as detected by MTT test were 30 microM for sodium chromate (Na2CrO4), 475 microM for cobalt chloride (CoCl2) and 600 microM for nickel chloride (NiCl2). Chromium chloride (CrCl3) was not toxic up to 1 mM. No clear effects were observed after 4 h, but 24-h treatments with 1 mM CoCl2 or 10 microM Na2CrO(4) were found to almost completely abolish the ability of the cells to form colonies, whilst 1 mM NiCl2 reduced cellular survival to only 70% of control cultures. Intracellular accumulation of metals was evaluated by the use of radioisotopes at the EC50 value and at 1/10-1/5 of this concentration. Accumulation of Na2(51)CrO4 was linear with increasing dose. This was not the case for 63NiCl2 and 58CoCl2. All the metals were accumulated preferentially in the cytosols; 96% or more for 63NiCl2, approximately 90% for 58CoCl2 and 60-70% for Na2(51)CrO4. Finally, it was observed that HaCaT human keratinocytes can concentrate the metals present in the media up to 3.9 and 12.5 times for NiCl2 and CoCl2, respectively, and up to 167 for Na2CrO4. These striking metal intracellular accumulation patterns, which have not been earlier described in keratinocytes, highlight the relevance of searching for specific biomarkers of early cellular toxic effects, such as cytosolic proteins that bind the metals.
Subject(s)
Chromium/metabolism , Chromium/toxicity , Cobalt/metabolism , Cobalt/toxicity , Keratinocytes/drug effects , Keratinocytes/metabolism , Nickel/metabolism , Nickel/toxicity , Cell Line , Cell Survival/drug effects , Colony-Forming Units Assay , Humans , Indicators and Reagents , Nitroblue Tetrazolium , Subcellular Fractions/drug effects , Subcellular Fractions/metabolismABSTRACT
Transgenic mice for genotoxicity testing have been developed, although no such models have been produced for the evaluation of toxic, nongenotoxic chemical compounds. We have developed a transgenic mouse model for the analysis of toxic inorganic compounds. We engineered a mouse lineage with the human growth hormone (hGH) gene under the control of the human hsp70 promoter, in which a plasma-detectable hGH response can be elicited by exposure to heat shock. In primary cell cultures from these mice, hGH release was observed following treatment with several toxic inorganics. Transgenic mice injected intraperitoneally with sodium arsenite, cadmium chloride, copper sulphate, or methylmercurium chloride showed significant hGH levels in plasma.
Subject(s)
HSP70 Heat-Shock Proteins/genetics , Human Growth Hormone/genetics , Liver/drug effects , Mutagenicity Tests , Xenobiotics/toxicity , Animals , Arsenites/administration & dosage , Arsenites/toxicity , Cadmium Chloride/administration & dosage , Cadmium Chloride/toxicity , Cells, Cultured/drug effects , Copper Sulfate/administration & dosage , Copper Sulfate/toxicity , Gene Expression Regulation/drug effects , Gene Expression Regulation/genetics , HSP70 Heat-Shock Proteins/blood , Human Growth Hormone/biosynthesis , Human Growth Hormone/blood , Humans , Injections, Intraperitoneal , Liver/metabolism , Methylmercury Compounds/administration & dosage , Methylmercury Compounds/toxicity , Mice , Mice, Transgenic , Models, Genetic , Polymerase Chain Reaction , Promoter Regions, Genetic , Sodium Compounds/administration & dosage , Sodium Compounds/toxicity , TransgenesABSTRACT
The preimplantation mouse embryo has been found to be a good model for various toxicological investigations. This communication deals with two examples of research activities carried out in our laboratory to detect the embryotoxic properties of tritium and of 1,2:3,4-diepoxybutene (DEB). Exposures of blastocysts for 24 hr to concentrations as high as 0.296 kBq/ml tritiated amino acids or nucleoside induced a statistically significant reduction in the percentage of embryos that reached the stage of two-layer inner cell mass (ICM). The same quantity of tritiated arginine, but not of thymidine or tryptophan, also induced a lower percentage of differentiating ICM than the control when added to culture medium during the second cleavage division. These findings support the idea that tritium released by nuclear power plants as HT or as tritiated water (HTO) could become a radiotoxicological problem since it can be converted easily into organic compounds by living organisms. DEB was found to be highly embryotoxic in preimplantation mouse embryos in vitro at micromolar concentrations. This compound is formed in mammalian cells by the oxidative metabolism of 1,3-butadiene, a chemical used in rubber industries and present in tobacco smoke. Again, the most sensitive stages of preimplantation development were found to be the two- and the four-cell embryos. These results were confirmed by in vivo measurements.
