title: Induction of chromosome damage in mouse bone marrow by benzo[a]pyrene.
abstract: The cytogenetic effects, in vivo, of the polycyclic hydrocarbon benzo[a]pyrene were studied in adult male mice by chromosome analysis and the micronucleus test. To establish the appropriate time for bone-marrow sampling, the interval between treatment and preparation was varied. The maximal response in the micronucleus test was found 36 h after treatment versus 30 h when chromosomal aberrations were analyzed. In the micronucleus test the lowest effective dose was 25 mg/kg, whereas a significant effect (P less than 0.001) was observed at 6.25 mg/kg when aberrations were used as the mutagenic end-point. The results show that, with single treatments and different sampling intervals applied in both tests, aberration analysis had a higher resolving power than the micronucleus test at the time of maximal response. A suitable protocol for routine application of the 2 bone-marrow tests is discussed in view of the guidelines presently under preparation in the EEC and the OECD. Arguments are presented against a sub-acute treatment regimen and for a single treatment regimen with multiple sampling intervals.
mesh_terms: D000818:Animals; D001580:Benzopyrenes / Q000494:pharmacology*; D001853:Bone Marrow / Q000648:ultrastructure; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D007621:Karyotyping; D008297:Male; D051379:Mice; D009152:Mutagenicity Tests; D009153:Mutagens; D013997:Time Factors
chemical_list: D001580:Benzopyrenes; D009153:Mutagens