RESUMO
Doxorubicin chlorhydrate (AdriblastinaR) is a glycoside anthracycline antibiotic that acts against a large number of tumors and is extensively used in human and veterinary oncology. Its nonselective cytostatic effect has led to contradictory informations about its mechanism of action and its hypoplasia-inducing effect on rapidly renewing cell systems such as those of hematopoietic tissue. A study was conducted on 15 adult male and female dogs of both sexes divided intro three groups: Group A, injected with 30 mg/m2 doxorubin in two applications separated by a 21 days interval; Group B, injected with 30mg/m2 doxorubin in four applications separated by weekly intervals; and a control group injected with placebo. Peripheral blood parameters were determined at 5 days intervals and a myelogram was obtained at 10 days intervals in all animals for a period of 50 days. The results showed a significant decrease in hematocrit, erythrocyte concentration and hemoglobin rate in the animals submitted to a total dose of 120mg/m2 doxorubicin. Periodic evaluation of central hematopoietic tissue (myelogram) did not reveal any measurable changes in erythropoietic, granulopoietic or megakaryocytopoietic activity, except by a discrete deflection in the lymphocytic series. In this way, under the experimental tested conditions, which mimic the recommended therapeutic doses of Doxorubicin, it was not observed, in healthy dogs, severe damage in the hematopoietic compartiment. Further studies are needed to contribute to the elucidation of the mechanism of action of the drug under study.