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Effects of α-tocopherol and astaxanthin on LDL oxidation and atherosclerosis in WHHL rabbits

      Abstract

      The aim of this study was to evaluate the influence of α-tocopherol and astaxanthin on low-density lipoprotein (LDL) oxidation lag time and atherosclerotic lesion formation in Watanabe heritable hyperlipidemic (WHHL) rabbits. Thirty-one, 3-month-old WHHL rabbits were divided into three experimental groups. One group (n=10) was fed standard rabbit feed alone and served as a control, a second group (n=11) was supplied with the same feed containing 500 mg α-tocopherol/kg and a third group (n=10) was given a feed containing 100 mg astaxanthin/kg. Plasma lipids, lipoproteins and LDL oxidation lag time were followed for 24 weeks. At the end of the treatment period, the animals were killed and the thoracic aorta was used for evaluation of the degree of atherosclerosis. Colour photographs of the intimal surface of the vessel were taken for determination of the atherosclerotic area. Cross-sections of the thoracic aorta were used for histological examination and for determination of intimal thickening. Specimens of the vessel were used for determination of the tissue cholesterol content. Plasma cholesterol remained at a high level during the time of the experiment and there were no differences between the experimental groups. After 24 weeks, the LDL oxidation lag time was 53.7±1.7 min, 109±4 min (P<0.001) and 56.4±3.4 min (P=0.47) in the control, α-tocopherol and astaxanthin groups, respectively. In the thoracic aorta, the atherosclerotic area was 80.7±5.1%, 67.1±6.7% (P=0.13) and 75.2±5.7% (P=0.49) in the control, α-tocopherol and astaxanthin groups, respectively. The intimal thickening was 45.6±3.2%, 44.0±4.1% (P=0.89) and 40.0±4.5% (P=0.33) in the control, α-tocopherol and astaxanthin groups, respectively. Finally, the cholesterol content was 107±9 μmol/g, 95.7±11.5 μmol/g (P=0.31) and 101±5 μmol/g (P=0.33) in the control, α-tocopherol and astaxanthin groups, respectively. It can be concluded that α-tocopherol but not astaxanthin prolonged the LDL oxidation lag time. The two antioxidative substances did not prevent atherogenesis in WHHL rabbits in this setting.

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      References

        • Lusis A
        Atherosclerosis.
        Nature. 2000; 407: 233-241
        • Steinberg D
        • Parthasarathy S
        • Carew T.E
        • et al.
        Beyond cholesterol: modifications of low density lipoprotein that increase its atherogenicity.
        New Engl. J. Med. 1989; 320: 915-924
        • Stephens N.G
        • Parsons A
        • Schofield P.M
        • et al.
        Randomised controlled trial of vitamin E in patients with coronary disease: Cambridge Heart Antioxidant Study (CHAOS).
        Lancet. 1996; 347: 781-786
      1. MRC/BHF Heart Protection Study Collaborate Group. MRC/BHF Heart Protection Study of antioxidant vitamin supplementation in 20536 high-risk individuals a radomized placebo-controlled trial. Lancet 2002;360:23–33.

        • Bocan T
        • Mueller S
        • Brown E
        • et al.
        Antiatherosclerotic effects of antioxidants are lesion-specific when evaluated in hypercholesterolemic New Zealand white rabbits.
        Exp. Mol. Pathol. 1992; 57: 70-83
        • Shaish A
        • Daugherty A
        • O’Sullivan F
        • et al.
        Beta-carotene inhibits atherosclerosis in hypercholesterolemic rabbits.
        J. Clin. Invest. 1995; 96: 2075-2082
        • Fruebis J
        • Steinberg D
        • Dresel H
        • et al.
        A comparison of the antiatherogenic effects of probucol and of a structural analogue of probucol in low density lipoprotein receptor-deficient rabbits.
        J. Clin. Invest. 1994; 94: 392-398
        • Kita T
        • Nagano Y
        • Yokode M
        • et al.
        Probucol prevents the progression of atherosclerosis in Watanabe heritable hyperlipidemic rabbits, an animal model for familial hypercholesterolemia.
        Proc. Natl. Acad. Sci. USA. 1987; 84: 5928-5931
        • Carew T
        • Schwencke D
        • Steinberg D
        Antiatherogenic effect of probucol unrelated to its hypocholesterolemic effect: evidence that antioxidants in vivo can selectively inhibit low density lipoprotein degradation in macrophage-rich fatty streaks and slow the progression of atherosclerosis in the Watanabe heritable hyperlipidemic rabbit.
        Proc. Natl. Acad. Sci. USA. 1987; 84: 7725-7729
        • Mao S
        • Yates M
        • Parker R
        • et al.
        Attenuation of atherosclerosis in a modified strain of hypercholesterolemic Watanabe rabbits with use of a probucol analogue (MDL 29,311) that does not lower serum cholesterol.
        Arterioscler. Thromb. 1991; 11: 1266-1275
        • Willingham A.K
        • Bolanos C
        • Bohanna E
        • et al.
        The effect of high levels of vitamin E on the progression of atherosclerosis in the Watanabe heritable hyperlipidemic rabbit.
        J. Nutr. Biochem. 1993; 4: 651-654
        • Mayne S.T
        Beta-carotene.
        FASEB. 1996; 10: 690-701
        • Matsuno T
        Xanthophylls as precursor of retinoids.
        Pure Appl. Chem. 1991; 63: 81-88
        • Miki W
        Biological functions and activities of animal carotenoids.
        Pure Appl. Chem. 1991; 63: 141-146
        • Prasad K
        • Kalra J
        Oxygen free radicals and hypercholesterolemic atherosclerosis: effects of vitamin E.
        Am. Heart J. 1993; 125: 958-973
        • Williams R.J
        • Motteram J.M
        • Sharp C.H
        • Gallagher P.J
        Dietary vitamin-E, and the attenuation of early lesion development in modified Watanabe rabbits.
        Atherosclerosis. 1992; 94: 153-159
        • Stähler F
        • Gruber W
        • Stinshoff K
        • Röschlau P
        Eine praxisgerechte enzymatische cholesterol-bestimmung.
        Med. Lab. 1977; 30: 29-37
        • Seidel J
        • Schlumberger H
        • Klose S
        • Ziegenhorn J
        • Wahlefeld A.W
        Improved reagent for the enzymatic determination of serum cholesterol.
        J. Clin. Chem. Clin. Biol. 1981; 19: 838-839
      2. Wahlefeld AW. Triglycerides. Determination after enzymatic hydrolysis. In: Bergmeyer UH, editor. Methods in enzymatic analyses. New York, USA: Academic Press; 1974. p. 1831–5.

      3. Hatch FT, Lees RS. Practical methods for plasma lipoprotein analysis. In: Paoletti R, Krichewsky D, editors. Advances in lipid research, vol. VI. New York, USA: Academic Press; 1968. p. 1–68.

        • Lopes-Virella M.F
        • Stone P
        • Ellis S
        • Cornwell J.A
        Cholesterol determination in high-density lipoproteins separated by three different methods.
        Clin. Chem. 1977; 23: 882-884
        • Kleinveld H.A
        • Hak-Lemmers H.L.M
        • Stalenhoef A.F.H
        • Demacker P.N.M
        Improved measurement of low-density-lipoprotein susceptibility to copper-induced oxidation application of a short procedure for isolating of low-density lipoprotein.
        Clin. Chem. 1992; 38: 2066-2072
        • Folch J
        • Lees M
        • Sloane Stanley G.H
        A simple method for the isolation and purification of total lipids from animal tissues.
        J. Biol. Chem. 1957; 226: 497-509
        • Hanel H.K
        • Dam H
        Determination of small amounts of total cholesterol by the Tshugaeff reaction with a note on the determination of lathosterol.
        Acta Chem. Scand. 1955; 9: 677-682
        • Watanabe Y
        Serial inbreeding of rabbits with hereditary hyperlipidemia (WHHL-rabbit).
        Atherosclerosis. 1980; 36: 261-268
        • Watanabe Y
        • Ito T
        • Shiomi M
        The effect of selective breeding on the development of coronary atherosclerosis in WHHL-rabbits. An animal model for familial hypercholesterolemia.
        Atherosclerosis. 1985; 56: 71-79
        • Iwamoto T
        • Hosoda K
        • Hirano R
        et al. Inhibition of low-density lipoprotein oxidation by astaxanthin.
        J. Atheroscler. Thromb. 2000; 7: 216-222