Induction of sister chromatid exchange in spleen and bone marrow cells of rats exposed by inhalation to different dose rates of ethylene oxide.
Ong-T; Bi-K; Xing-S; Stewart-J; Moorman-W
Environ Mol Mutagen 1993; 22(3):147-151
The influence of dose rate on sister chromatid exchange (SCE) induction in spleen and bone marrow cells by ethylene-oxide (75218) (EtO) vapor was studied in rats. Male Fischer-344-rats were exposed to 100 parts per million (ppm) EtO vapor 6 hours daily (low dose rate), 300ppm EtO 2 hours daily (medium dose rate), or 600ppm EtO for 1 hour daily (high dose rate), 5 days a week for 3, 6, or 9 months. The dosing protocol was designed to ensure that all rats received the same total integrated EtO exposure, 600ppm hours. Selected rats were killed after 3, 6, or 9 months and the spleens and femurs were removed. The femoral bone marrow was flushed out. Spleen and bone marrow cells were scored for SCEs. EtO induced SCEs in both spleen and bone marrow cells. The increases were statistically significant for all treatment groups at each time point except in bone marrow cells from rats exposed at the medium and high dose rates for 3 months. The overall SCE frequencies were higher in spleen cells than in bone marrow cells. The increases in SCE frequency in splenocytes were similar at all dose rates. The largest induction of SCEs in bone marrow cells occurred in the low dose rate groups. The authors conclude that inhalation exposure to EtO induces SCEs in spleen and bone marrow cells of Fischer-344- rats. Spleen cells are more sensitive to EtO than bone marrow cells.
NIOSH-Author; Oxides; In-vivo-studies; Laboratory-animals; Bone-marrow; Inhalation-studies; Splenic-tissue; Alkylating-agents; Genotoxic-effects; Dose-response
Environmental and Molecular Mutagenesis