Ultrastructural studies on the myocardial capillaries of the experimentally lathyritic rat, protective effect of certain flavonoids.

The ultrastructure of rat myocardial capillaries was studied in the course of experimental lathyrism. Endothelial cells were hypertrophic, with a sinuous profile of the plasma membrane facing the lumen and with a consistent increase of pinocytotic vesicles; the nuclei were irregular in shape; ATPase activity was no more demonstrable. Therefore, various and well distinct structural endothelial mechanisms seem to be primarily involved, causing an alteration of the dynamics of transcellular exchanges and of the permeability of the vascular wall. Simultaneous treatment with certain flavonoids, (O-(beta-hydroxyethyl)-rutosides and Na(+)-epicatechin-2-sulfonate), resulted in a less pronounced alteration and a more rapid recovery. The possibility of the existence of a common site of action of lathyrogens and flavonoids is raised in the discussion.