COMPARISON OF ADRIAMYCIN-INDUCED NUCLEOLAR SEGREGATION IN SKELETAL-MUSCLE, CARDIAC-MUSCLE, AND LIVER-CELLS

Abstract

Male Sprague-Dawley rats were treated with 2.5, 3.5 or 5.0 mg/kg of the antitumor agent adriamycin by i.v. injection. After 1 or 3 h of treatment, samples of liver, cardiac muscle and skeletal muscle cells were examined by EM. The changes in ultrastructure observed in these tissues after the 1st hour included nucleolar segregation and altered distribution of the perinucleolar chromatin. No alterations in the ultrastructure of the nucleus or cytoplasm were observed in tissues examined 3 h after a 5-mg/kg dose of adriamycin. The doses at which nucleolar alterations occurred varied between tissues. In skeletal and cardiac muscle cells, marked alterations in nucleolar ultrastructure were observed at doses of 3.5 and 5.0 mg/kg of adriamycin. Liver cell nucleoli exhibited few structural aberrations at these doses. The similarities in response of skeletal and cardiac muscle suggest that ultrastructural analysis of skeletal muscle biopsies may be ulseful in evaluating adriamycin cardiotoxicity.