Ultrastructural signs of cyclophosphamide-induced damage to cardiomyocytes.

Ultrastructural changes in rat cardiomyocytes were studied after single administration of cyclophosphamide in the therapeutic dose. The major signs of cyclophosphamide-induced damage to cardiomyocytes included moderate lysis of myofibrils, dilation of vesicles in the granular and agranular sarcoplasmic reticulum, and destruction of mitochondria with the formation of myelin-like residual bodies. Ultrastructural changes in cardiomyocyte nuclei primarily manifested in variations of the shape, deep invaginations of the nuclear membrane, and translocation into the subsarcolemmal region.