title: Alterations in immune parameters associated with low level methylmercury exposure in mice.
abstract: Methylmercury (MeHg) is a known toxicant and continues to be a significant environmental contaminant. While the neurotoxicity and developmental toxicity of MeHg are well established, the immunotoxic effects of MeHg are just now being studied and described. This study evaluated strain and gender specific effects of low level, prolonged MeHg exposure in mice. Mice were exposed to MeHg in the drinking water (0, 3 or 10 ppm) for 4 weeks. Splenocytes and thymocytes were evaluated for alterations in immunophenotype, GSH levels, and intracellular Ca2+ flux after mitogen stimulation. MeHg exposure resulted in alterations in splenocyte and thymocyte subsets and a dose dependent decrease in GSH levels (as measured by monochlorobimane fluorescence and flow cytometry) of all splenocyte subsets. This decrease in GSH was further confirmed by biochemical assay in splenocytes. In addition, there was a dose response related decrease in mitogen stimulated Ca2+ flux and in the percentages of CD4+ splenocytes and CD8+ splenocytes from mice exposed to 10 ppm of MeHg. These results suggest that low-level chronic MeHg exposure may cause immune disfunction by disturbing thiol redox balance, transmembrane signaling and splenic cellularity.
authors.affiliation: Department of Environmental Health, University of Washington, Seattle 98115, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Thompson
authors.forename: K L
authors.initials: KL
authors.lastname: Roellich
authors.forename: A
authors.initials: A
authors.lastname: Grossmann
authors.forename: S G
authors.initials: SG
authors.lastname: Gilbert
authors.forename: T J
authors.initials: TJ
authors.lastname: Kavanagh
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D005260:Female; D005434:Flow Cytometry; D005978:Glutathione / Q000378:metabolism; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008297:Male; D008767:Methylmercury Compounds / Q000633:toxicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D015398:Signal Transduction / Q000187:drug effects; D013154:Spleen / Q000166:cytology* / Q000187:drug effects; D013950:Thymus Gland / Q000166:cytology* / Q000187:drug effects
chemical_list: D008767:Methylmercury Compounds; D005978:Glutathione; D002118:Calcium