The addition of 10 % dried fruiting bodies of the oyster mushroom (Pleurotus ostreatus) to the diet containing 1 % of cholesterol reduced serum cholesterol levels by 65 % and cholesterol content in the liver, heart, long extensor muscle and aorta of male rabbits (Chinchilla) by 60; 47; 25 and 79 %, respectively. Oyster mushroom diet reduced the content of conjugated dienes by 60–70 % in the plasma, erythrocytes and liver. However, it did not significantly affect the activities of antioxidant enzymes. Oyster mushroom diet reduced significantly the incidence of atherosclerotic plaques as estimated by sudanophilia (absence of a positive reaction in 3 of 5 animals) as well as plaque size (26 % vs. 2 % of the area with a positive reaction in control and oyster mushroom-treated animals, respectively). While all animals on control diet showed atherogenic changes in the aorta, oyster mushroom diet prevented the development of these changes in three animals. Fatty streaks and fibromatous plaques were found in the remaining two animals from this group. The oyster mushroom prevented the formation of atheroma plaques (found in three cases from the control diet group) and reduced the incidence of segmental injury of the coronary artery and of focal fibrosis of the myocardium. The oyster mushroom caused lower incidence of foam cells in all types of lesions.

        Key words: rabbit – cholesterol diet – oyster mushroom (Pleurotus ostreatus) – atherosclerosis