Introduction: β-Carotene-rich diet has been shown to be inversely associated with the risk of coronary heart disease. However, clinical trials using synthetic all-trans-β-carotene failed to demonstrate a beneficial effect. We therefore sought to study the effect of natural source of β-carotene, the alga Dunaliella, containing both all-trans and 9-cis-β-carotene on atherosclerosis. In a previous study we showed that 9-cis-β-carotene-rich powder of the alga Dunaliella inhibits early atherogenesis in low-density lipoprotein receptor knockout mice.
Aims: The aims of the current work were to study whether diet enriched with Dunaliella powder would inhibit the progression of established atherosclerosis in old male apoE-deficient mice and to compare the effect of Dunaliella on lipid profile and atherosclerosis in a low-versus high-fat diet fed mice.
Methods: In the first experiment, young mice (12 weeks old) were allocated into 3 groups: (1) low-fat diet; (2) low-fat diet + Dunaliella powder (8%); (3) low-fat diet + β-carotene-deficient Dunaliella. In the second experiment, old mice (7 months old) with established atherosclerotic lesions were allocated into 4 groups: (1) low-fat diet; (2) low-fat diet + Dunaliella; (3) high fat-diet; (4) high-fat diet + Dunaliella.
Results: In young mice fed a low-fat diet, a trend toward lower atherosclerotic lesion area in the aortic sinus was found in the Dunaliella group compared with the control group. In old mice with established atherosclerotic lesion, Dunaliella inhibited significantly plasma cholesterol elevation and atherosclerosis progression in mice fed a high-fat diet.
Conclusion: The results of this study suggest that a diet containing natural carotenoids, rich in 9-cis-β-carotene, has the potential to inhibit atherosclerosis progression, particularly in high-fat diet regime.