Cellular breakdown within muscular arteries in hypercholesterolemic rats.

Adult male rats were fed a high-fat cholesterol, thyroid-suppressive diet for three months, after which the structure of the muscular arteries (coronary and tarsal pedis) was examined by transmission electron microscopy. The plasma cholesterol concentration was elevated when the animals were killed and a distinct ultrastructural finding was the presence of necrotic cells in the media of both the coronary and the tarsal pedis arteries. Medial smooth muscle cells contained multivesicular membranous bodies, and membranous material accumulated in the intercellular space of the arterial media. It is proposed that the membrane changes and cellular death within muscular arteries may primarily be due to the increased membrane cholesterol concentration of smooth muscle cells during hypercholesterolemia. Dietary saturated fatty acids may have a contributing effect on smooth muscle cell injury in the hypercholesterolemic state.