Hypocholesterolemic and antiatherogenic effect of oyster mushroom (Pleurotus ostreatus) in rabbits.

The addition of 10% dried fruiting bodies of oyster mushroom (Pleurotus ostreatus) to the diet containing 1% of cholesterol reduced serum cholesterol levels by 65% and cholesterol content in liver, heart, long extensor muscle and aorta of male rabbits (Chinchilla) by 60, 47, 25 and 80%, respectively. The decrease in total serum cholesterol was affected primarily (by 70%) by reduced cholesterol content in very-low-density lipoproteins (VLDL) while the contribution of high density lipoproteins (HDL) cholesterol increased by a factor of 3. Oyster mushroom diet reduced by 60-70% the content of conjugated dienes in plasma, erythrocytes and liver, however, it did not affect significantly the activities of antioxidant enzymes. Oyster mushroom diet reduced significantly the incidence of atherosclerotic plaques as estimated by sudanophilia (absence of positive-reaction in 3 of 5 animals) as well as plaque size (26% vs. 2% of the area with positive reaction in control and oyster mushroom-treated animals, respectively). While all animals on control diet showed atherogenic changes in 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. 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 coronary arteria and of focal fibrosis of myocardium. Oyster mushroom caused lower incidence of foam cells in all types of lesions.