[Changes in the muscle fiber induced by p-phenylenediamine in the rat].

P-phenylenediamine (PPD) induces skeletal muscle lesions in rats which have been chosen as a model for investigation of the inflammatory and degenerative pattern of the muscle fibers. With the use of histochemical and ultrastructural criteria, the morphology of the lesions have been analysed in the diaphragm. Fifteen minutes after the induction by PPD, a subsarclemmal oedema can be shown by electron microscopy. Enzymatic changes appear during the first hour. The pathologic features are more prominent after twenty-four hours. The lesions are characterized by a segmental necrosis adjacent to unaltered fibers and by particular types of fibers such as target, snake coils, core fiber. A comparison between the lesions induced by PPD and those occurring during other types of myopathies has been made.