title: Assessment of apoptosis in thymocytes and splenocytes from mice exposed to arsenate in drinking water: cytotoxic effects of arsenate on the cells in vitro.
abstract: This study provides an assessment of the level of apoptosis in thymocytes and splenocytes from mice exposed to arsenate in drinking water. To simulate the naturally occurring exposure conditions of humans, the animals were exposed to arsenate at the concentrations of 0.5, 5, and 50 mgAs/L. TUNEL method for staining of thymocytes and splenocytes isolated from the mice after 8 and 12 weeks revealed increased percentage of apoptotic cells in the exposed groups. Although statistically significant increases were observed only for the highest concentration of arsenate, the increases showed linear trend as a function of arsenate concentration in drinking water. In vitro experiments performed on isolated cells incubated for 24 hours with arsenate at 6.7-2000 microM showed very similar concentration-viability relationships for both cell populations (IC50 was 442+/-15 microM and 427+/-18 microM for thymocytes and splenocytes, respectively). Arsenate induced a concentration-dependent increase in the percentage of the cells undergoing apoptosis. At higher concentrations, apoptosis was the predominant mode of cell death. It can be speculated that proapoptotic effects of arsenate as observed in our in vivo study may contribute to some immunotoxic symptoms observed in people chronically exposed to arsenic in drinking water.
authors.affiliation: Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, Lódź, Poland. mstep@imp.lodz.pl
authors.forename: Maciej
authors.initials: M
authors.lastname: Stepnik
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Stańczyk
authors.forename: Joanna
authors.initials: J
authors.lastname: Arkusz
authors.forename: Dobrosława
authors.initials: D
authors.lastname: Lewińska
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001149:Arsenates / Q000633:toxicity*; D018929:Cell Culture Techniques; D005260:Female; D006801:Humans; D020287:In Situ Nick-End Labeling; D051379:Mice; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology; D013950:Thymus Gland / Q000166:cytology; D014873:Water Pollutants / Q000633:toxicity*; D014881:Water Supply
chemical_list: D001149:Arsenates; D014873:Water Pollutants; C025657:arsenic acid