Short term toxicity of nitrous oxide on the immune, hemopoietic, and endocrine systems in CD-1 mice.
Occupational exposures to subanesthetic levels of N2O have been documented to result in suppressed proliferative cell activities. Male CD-1 mice were exposed to 0, 50, 500, and 5000 ppm of N2O for 6 hr/day, 5 days/week for 2 or 13 weeks. Tritiated-thymidine ([3H]-TdR) uptake was measured in CD-1 splenic lymphocytes cultured with and without mitogens and in a mixed lymphocyte culture (MLC). Antibody-mediated immunocompetency was determined for sheep red blood cell (SRBC)-sensitized animals by plaque forming cell (PFC) assay and serum anti-SRBC antibody (Ab) titer. Deoxyuridine suppression tests (dUrdST) were performed on bone marrow cells. There was significantly decreased splenic lymphocyte uptake of [3H]-TdR by cells cultured with mitogenic substances and in MLC following 2-week exposures to 5000 ppm. After 13-week exposures the animals' splenic lymphocytes showed increased [3H]-TdR uptake following high N2O dosing in both the mitogen-induced blastogenesis and MLC assays. Compared to control animals, the 5000 ppm exposure group had significantly depressed PFC activity and circulating anti-SRBC Ab levels following the 13-week N2O exposures, and all 13-week exposure groups demonstrated decreased liver weights and leukopenia. Bone marrow activity at these dosing levels was depressed in a dose-dependent fashion following 13-week gas exposures.
Healy
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Department of Biology, Utah State University, Logan 84322-5305.
Drown
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Sharma
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D000818:Animals; D001772:Blood Cell Count; D001835:Body Weight / Q000187:drug effects; D003857:Deoxyuridine; D004702:Endocrine Glands / Q000187:drug effects*; D006413:Hematopoietic System / Q000187:drug effects*; D006462:Hemolytic Plaque Technique; D006728:Hormones / Q000097:blood; D007107:Immune System / Q000187:drug effects*; D007075:Immunoglobulin M / Q000032:analysis; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009609:Nitrous Oxide / Q000633:toxicity*; D009929:Organ Size / Q000187:drug effects
D006728:Hormones; D007075:Immunoglobulin M; D009609:Nitrous Oxide; D003857:Deoxyuridine