Chromosomal Patterns of Irradiated Leukemic and Nonleukemic C57BL/6J Mice2

Publisher Website
Google Scholar
Abstract
Chromosomes of 17 C57BL/6J mice receiving 600 r total-body X irradiation were analyzed and compared to chromosomes of 6 normal mice. Seven mice developed leukemia and 10 did not. Chromosomes of 4 leukemic mice were examined. Mouse #1 (generalized leukemia) had cells with a mode of 40, variation above the mode, and a large marker chromosome. Mouse #2 (localized thymic leukemia) had 2 hyperdiploid modes of 41 and 42 in thymic tissue, but normal chromosomes were in the spleen and marrow. Mouse #3 (generalized leukemia) had modes of 40 and 41 in the thymus, spleen, and marrow. Mouse #4 (localized thymic leukemia) had a modal number of 41 with variation about the mode. One of the 10 irradiated nonleukemic mice had some cells with a pseudodiploid karyotype containing a minute chromosome, and another had a questionable abnormality consisting of increased variation about the mode. The remaining 8 mice had normal chromosomes. Aneuploidy in irradiated nonleukemic mice may be due to preleukemia or to persistent X-ray induced aberrations. The possibility of persistent chromosomal alterations after X ray suggests irradiation leukemias are not ideal for evaluation of the significance of aneuploidy in mouse preleukemia or leukemia.