title: An in vivo/in vitro method for assessing micronucleus and chromosome aberration induction in rat bone marrow and spleen. 2. Studies with chlorambucil and mitomycin C.
abstract: An in vivo/in vitro system using rat bone marrow cells and spleen cells to assess micronucleus (MN) and structural chromosome aberrations (SCA) simultaneously (Moore et al., 1995) was further developed. In two separate experiments, two rats/dose/experiment were treated i.p. with 0, 5, 10 and 15 mg chlorambucil (CA)/kg or with mitomycin C (MMC) at 0, 1, 2, 4 mg/kg (experiment 1) or 0, 4, 6, and 8 mg/kg (experiment 2) and killed 6 h later. Cultures were then established in the presence of growth stimulants (interleukin-3 and granulocyte-macrophage colony stimulating factor for bone marrow; lipopolysaccharide and concanavalin A for spleen) and cytochalasin B, a cytokinesis inhibitor. Bone marrow cells were harvested 24 h after establishment of cultures, while spleen cells were harvested at 48 h. In addition, spleen cells were concurrently assayed for chromosome aberrations. With the MN endpoint, spleen cells appeared more sensitive than bone marrow cells to the effects of CA due both to a lower background and an increased response. For MMC, bone marrow cells exhibited both a higher background of MN and a greater numerical response than did spleen cells. However, on the basis of a fold-increase over control values, spleen cells were more sensitive than bone marrow cells. In general, the MN endpoint appeared more sensitive than the SCA in spleen cells after treatment with CA or MMC. Thus, the approach described here shows greater potential in detecting genotoxicity.
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects / Q000648:ultrastructure; D002699:Chlorambucil / Q000633:toxicity*; D002869:Chromosome Aberrations; D005069:Evaluation Studies as Topic; D066298:In Vitro Techniques; D008297:Male; D015162:Micronucleus Tests / Q000379:methods*; D016685:Mitomycin / Q000633:toxicity*; D009152:Mutagenicity Tests / Q000379:methods*; D009153:Mutagens / Q000633:toxicity*; D009928:Organ Specificity; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000187:drug effects / Q000648:ultrastructure
chemical_list: D009153:Mutagens; D002699:Chlorambucil; D016685:Mitomycin