[Regulation of cholesterol metabolism with dietary addition of oyster mushrooms (Pleurotus ostreatus) in rats with hypercholesterolemia].
BACKGROUND
It is generally accepted that lowering of serum cholesterol levels reduces the risk of atherosclerosis. Identification and characterization of natural substances with hypocholesterolemic activity useful in dietetic prevention or treatment of hypercholesterolemia is still relevant in countries with persistent progression of hypercholesterolemia. Addition of oyster mushroom (Pleurotus ostreatus), an industrially produced wood-rotting fungus, to the diet effectively reduced cholesterol accumulation in serum and liver of rats fed a cholesterol diet. The aim of a series of experiments was to explain the biochemical mechanism of this effect.


RESULTS
Male Wistar rats fed a cholesterol (0.3%) diet shortly after weaning for a period of 8-10 weeks were used in the experiments. The addition of 5% of dried oyster mushroom to the diet had following effects: reduction of cholesterol level both in serum (5.12 +/- 0.55 vs. 3.44 +/- 0.16 mmol/l, p < 0.02) and liver (241 +/- 12 vs. 113 +/- 11 mmol/kg, p < 0.001); redistribution of cholesterol in favour of high-density lipoproteins; reduced production of very-low-density lipoproteins (135 +/- 7 vs. 96.5 +/- 5 mumol/h/kg, p < 0.001); reduced cholesterol absorption (61.2 +/- 2 vs. 53 +/- 2%, p < 0.02) and reduced HMG-CoA activity in liver (137 +/- 16 vs. 86 +/- 9 pmol/min/mg proteins, p < 0.02). Simultaneously, an increase in 7 alfa-hydroxylase activity in liver (17 +/- 1 vs. 22 +/- 1 pmol/min/mg proteins. p < 0.02) and bile acid excretion (7 +/- 0.9 vs. 11 +/- 0.5 mg/day/rat, p < 0.02) was observed. (Values shown are means +/- SEM.)


CONCLUSIONS
Biochemical mechanism of hypocholesterolemic effect of oyster mushroom on cholesterol-fed rats includes reduced production of cholesterol-rich very-low-density and low-density lipoproteins which principally determine cholesterol levels in serum. This effect is related to decreased absorption and biosynthesis of cholesterol together with increase in cholesterol catabolism and excretion of degradation products-bile acids.
Bobek
P
P
Výskumný ústav výzivy, Bratislava.
Ozdín
L
L
Kuniak
L
L
Hromadová
M
M
D000818:Animals; D002784:Cholesterol / Q000378:metabolism*; D006937:Hypercholesterolemia / Q000178:diet therapy* / Q000378:metabolism; D008297:Male; D011124:Polyporaceae; D051381:Rats; D017208:Rats, Wistar
D002784:Cholesterol