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Reciprocal Translocation in Somatic and Germ Cells of Mice Chronically Exposed by Inhalation to Ethylene Oxide: Implication for Risk Assessment
Donner, E., B. A. Wong, A. James, AND J. PRESTON. Reciprocal Translocation in Somatic and Germ Cells of Mice Chronically Exposed by Inhalation to Ethylene Oxide: Implication for Risk Assessment. MUTAGENESIS. Oxford University Press, Cary, NC, 25(1):49-55, (2010).
Groups of male B6C3F1 mice were exposed by inhalation to 0, 25, 50, 100 or 200 ppm EO for up to 48 weeks (6 hours/day, 5 days/week). Animals were sacrificed at 6, 12, 24, and 48 weeks after the startt of the exposure for analyses of reciprocal translocations in peripheral blood lymphocytes and germ cells. The frequency of the total chromosomal aberrations in the peripheral blood lymphocytes was significantly increased at the 100 and 200 ppm exposure concentrations at the 12 week time point, at 50, 100, and 200 ppm at the 24 week time point, and at all concentrations at the 48 week time point. The frequency of stable reciprocal translocations, which can be used as biomarkers, was increased (p<0.05) at 100 and 200 ppm at the 48 week time point. No statistically significant increase could be observed in translocation frequencies at the 6 week time point in the peripheral blood limphocytes. The exposure-response curves were non-linear when the frequencies of translocations were plotted against exposure durations or against exposure concentrations.
There was no effect of exposure concentration rate on recypriocal translocation frequency. In the spermatocytes, statistically significant increases could be observed in translocation frequencies at all concentrations at 48 weeks. However, it should be noted that increases were small and they did not occur in a dose responsiblve manner. The statistically significant increase observed at 12 weeks in the spermatocytes was considered to be equivocal as discussed.
Record Details:Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB
ASSOCIATE DIRECTOR FOR HEALTH