Effect of skim milk on progression of atherosclerosis in cholesterol-fed rabbits.

Effect of skim milk on progression of atherosclerosis was studied in cholesterol-fed rabbits. Rabbits were given a high cholesterol food (0.5%) with skim milk powder (16%) or no milk (control group). At 12 wk, the plasma cholesterol level was significantly higher in the control group (1605 mg/d1) than in the milk-fed group (1146 mg/d1). The contents of esterified cholesterol and elastin in the aorta were higher in the control group than in the milk-fed group by 28 an 94 per cent, respectively. The differences between the two groups in the contents of aortic triacylglycerols, mucopolysaccharides, collagen and unesterified cholesterol were not significant. The difference in sudanophilic area in the aorta between the control (35%) and the milk-fed groups (31%) was not significant. However, intimal proliferation and medial involvement in the aortic lesions were more severe in the control group. These findings suggest that skim milk can slow down the process of cholesterol induced atherogenesis.

Effect of skim milk on cholesterol induced blood platelet hyperaggregability in rabbit.

Effect of high cholesterol diet on blood platelet aggregation, and the influence of skim milk on cholesterol induced platelet hyperaggregability were studied in rabbits. The level of aggregated platelets (AP) increased to 19900/mm3 and that of plasma cholesterol to 1605mg/dl, while platelet aggregate ratio (PAR) decreased to 0.32 in rabbits fed high cholesterol diet (0.5% cholesterol) for 12 wk. The levels of AP (12500/mm3) and plasma cholesterol (1196mg/dl) were lower, and the PAR (0.46) was higher in rabbits which received the cholesterol diet supplemented with 16 per cent skim milk powder. In the second experiment, hypercholesterolaemia and platelet aggregation were induced in rabbits by high cholesterol diet given for 6 wk. The animals then received cholesterol-free diets for 8 wk, one group receiving the diet supplemented with 16 per cent skim milk powder and the other without milk served as the control group. The mean PAR in the milk powder supplemented group was restored to normal at 6 wk, while in the control group the level continued to be lower even up to 8 wk. The results thus demonstrate that the milk can prevent the process of cholesterol induced platelet aggregation.