Adriamycin, one of the antibiotic anticancer drugs, has been isolated from the Streptomyces peucetius caesiue. It is known that adriamycin inhibits DNA and RNA synthesis, and has been widely used as an anticancer drug. But the drug has so little specificity toward the normal and tumor cells that it induces many toxicity, alopecia, bone marrow depression and ulcer. And adriamycin also alters the biological func-
tions of the membrane by peroxidation of membrane unsaturated fatty acids. r
Therefore the author undertook the present study to pursue the effect of adriamycin on the cytoplasmic organelles of cardiac muscle cells.
Albino mice,DDY strains, weighing 20gm were used as an experimental animals.
The experimental animals were killed at 24 and 48 hours after administration of d 15mg/kg of adriamycin. The specimens obtained from the left ventricle of the heart were prefixed in Millonig´s solution and post-fixed in osmic acid. After dehydrating and embedding the specimens, ultrathin sections were made and double stained with uranyl acetate and lead citrate. And these preparations were observed with JEM 100cx-II electron microscope.
The results obtained were as follows.
1. Electron density at the I-band was decreased due to the discontinuation and loss of myofibrils in the 24 hour adriamycin treated group, but changes of myofibrils were recovered in the 48 hour adriamycin treated group.
2. Cisternae of the sarcoplasmic reticulum were dilated, fragmented and its sac culated
residues were found in the sarcolemma in the adriamycin treated group.
3. Mitochondria were swollen and their cristae were lost in the 12 hour adriamycin
treated group, but mitochondria were recovered in the 48 hour adriamycin treated
group.
Consequently, it is suggested that adriamycin would induce the cellular toxicity in the cardiac muscle cells, but the toxicity would be recovered as the time goes by.
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