DETERMINING RÔLE OF AGE AND THYMUS IN PATHOLOGY OF 7, 12-DIMETHYLBENZ[a]ANTHRACENEINDUCED LEUKEMIA IN MICE

Abstract

High yield of leukemia induction is consistently observed in Swiss mice injected with a single dose of lipid emulsion of 7, 12-dimethylbenz[a]anthracene (DMBA) at both neonatal and adult ages. However, the prevalent types of leukemias thus evoked may differ depending on the age of animals when DMBA is given. Thymic lymphocytic leukemia is most frequent when the chemical is given at neonatal age, whereas undifferentiated cell leukemia without thymus involvement is common when the chemical is injected at adult age. Frequent occurrence of thymic lymphocytic leukemia is also observed in adult mice by injection of DMBA either at postpartum period or after a single injection of cortisone acetate. Thymuses in these conditioned animals showed prompt decrease in weight due to marked depletion of lymphocyte population which was followed by rapid increase in weight due to lymphocyte proliferation. Thymuses in such situations may be comparable to the thymus at the neonatal age.