Fluorescence in sections of cardiac muscle from rats acutely treated with 4'-0-tetrahydropyranil-adriamycin hydrochloride (THP)

An investigation was undertaken of the capacity of thepirubicin (THP), a new anthracycline derivative with reduced cardiotoxicity, to be fixed in the myocardial fibre, as compared with that of adriamycin hydrochloride (ADR), using a method based on the histofluorescence of tissues treated in vivo with anthracyclines. Histological examination of heart sections from rats perfused with either THP or ADR showed similar results. The major difference was the lower quantitative localization of THP in the cytoplasm, although this quantitative difference was not so pronounced in the nuclei. This suggests that cardiac lesions may be due not to the basic action of anthracyclines on DNA but to collateral effects not yet identified.