Occurrence of intramitochondrial Ca2+ granules in a hypertrophied heart exposed to adriamycin

Abstract

Left ventricular hypertrophy was produced in rabbits by narrowing the abdominal aorta in the subdiaphragmatic region. Six weeks after the surgery, sham control as well as hypertrophied animals were treated with adriamycin. Myocardial cell damage resulting from a total cumulative dose of 5 mg/kg of adriamycin was seen only in hypertrophied hearts. Alterations in muscle cells of these hearts included prominent "contraction bands" and perinuclear edema. Mitochondria were characterized by swelling and accumulation of electron-opaque granules. Energy-dispersive x-ray analysis of the mitochondria revealed the presence of calcium in these granules. The study confirms that the hypertrophied heart is more vulnerable to adriamycin-induced cell damage and this may be due to an increased susceptibility of these hearts to the occurrence of Ca²⁺ overload in the cell.