Red and black rice decrease atherosclerotic plaque formation and increase antioxidant status in rabbits

Abstract

The influence of white, red and black rice consumption on atherosclerotic plaque formation induced by hypercholesterolemia was investigated in rabbits. Male rabbits (n = 36) were divided into five groups. They were fed a normal laboratory purified diet (normal group, n = 6), a high cholesterol (0.5 g/100 g) diet (HC group, n = 6), a high cholesterol diet with 30 g/100 g white rice (WR group, n = 8), 30 g/100 g red rice (RR group, n = 8), or 30 g/100 g black rice (BR group, n = 8) for 10 wk. Blood samples were collected for lipid measurements and aorta were removed for assessment of atherosclerotic plaques at the end of the protocol. The oxidant and antioxidant status of blood, erythrocytes, liver and aorta was evaluated. The area of atherosclerotic plaque was 50% lower in rabbits fed the red or black rice diets than in those fed the white rice diet. Compared with the HC and WR groups, serum HDL cholesterol and apolipoprotein (apo) A-I concentration were greater (P < 0.05) in the RR and BR groups. Liver reactive oxygen species (ROS) and aortic malondialdehyde (MDA) were significantly lower, and the liver total antioxidative capacity (TAC) and erythrocyte superoxide dismutase (SOD) activity were significantly higher in the RR and BR groups compared with the HC and WR groups. Red or black rice consumption reduced or retarded the progression of atherosclerotic plaque development induced by dietary cholesterol. The enhanced serum HDL cholesterol and apo A-I concentrations, and the increased antioxidant and decreased oxidative status may be mechanisms of the antiatherogenic effect of red or black rice.