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VEHICLE AND MODE OF ADMINISTRATION EFFECTS ON THE INDUCTION OF ABERRANT CRYPT FOCI IN THE COLONS OF MALE F344/N RATS EXPOSED TO BROMODICHLOROMETHANE
Citation:
Geter, D. R., M H. George, T. M. Moore, S. R. Kilburn, G. HugginsClark, AND A B. DeAngelo. VEHICLE AND MODE OF ADMINISTRATION EFFECTS ON THE INDUCTION OF ABERRANT CRYPT FOCI IN THE COLONS OF MALE F344/N RATS EXPOSED TO BROMODICHLOROMETHANE. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH 67(1):23-29, (2004).
Description:
Vehicle and Mode of Administration Effects on the Induction of Aberrant Crypt Foci in the Colons of Male F344/N Rats Exposed to Bromodichloromethane.
David R. Geter, Michael H. George, Tanya M. Moore, Steve Kilburn, Gloria Huggins-Clark, and Anthony B. DeAngelo. Submited to the Journal of Toxicology and Environmental Health. Publication date: Fall, 2003
Abstract
Bromodichloromethane (BDCM) and tribromomethane given by corn oil gavage were previously found to induce neoplasia in the large intestine of rats. Our chronic bioassay of BDCM administered in drinking water failed to produce colon neoplasia in male F344/N rats. We recently reported that BDCM induces aberrant crypt foci (ACF), putative precursor lesions in the development of colon cancer, when included in the drinking water of male rats. To investigate whether ACF induced by BDCM could be promoted by corn oil (CO), male F344/N rats were exposed to 0.7 g BDCM/L in drinking water or 50 mg BDCM/kg body weight by oral gavage in CO. Animals exposed to drinking water, CO, or 15 mg/kg azoxymethane (AOM) (i.p.) constituted the negative, vehicle and positive controls. After 26 weeks colons were examined for ACF. A significant decrease in water consumption was observed in both the positive controls and BDCM treated animals, however no difference was noted in final body weight. The administration of CO to AOM exposed animals produced a significant increase in total ACF when compared to AOM alone. BDCM produced a significant increase in ACF when compared to control but no difference was noticed between BDCM exposed by oral CO gavage. Additionally, no difference was noted between BDCM exposed by drinking water or oral CO gavage. This study demonstrates that the formation of ACF is independent of the route of BDCM exposure (drinking water vs. oral corn oil gavage) with both routes producing similar ACF values of 1.33 ? 0.49 and 1.5 ? 0.51 ACF/colon.