Effects of soybean oil and beta-carotene on lipid peroxidation and antioxidant enzymes activities in primary rat hepatocytes

• Main Authors: Chan-Ching Chiang, 江貞慶
• Other Authors: Hsing-Hsien Cheng
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/09390857972060524713

碩士 === 台北醫學院 === 保健營養學研究所 === 89 === Soybean oil is the main source of dietary polyunsaturated fatty acids. Several studies have shown that high intake of polyunsaturated fatty acids promotes lipid peroxidation. -carotene (BC) is one of the prevalent carotenoids in diets and also a scavenger of singlet oxygen. Indices of lipid peroxidation are lowed by BC supplements. In order to investigate the effects of soybean oil and BC on lipid peroxidation, rats were supplemented 400 L soybean oil and 40 mg BC daily by gavage for 4 weeks. Then, hepatocytes were isolated by two-step collagenase perfusion and incubated in medium which contained 0.01, 0.1, 0.5 or 1 mM -linolenic acid (ALA) to induce lipid peroxidation. Results indicate that medium contained 0.5 or 1 mM ALA increased cellular malondialdehyde (MDA) concentration and decreased superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) activities significantly. Soybean oil supplementation decreased GSHPx and catalase activities and raised the ratio of linoleic acid and ALA within the cell. BC supplementation enhanced cellular BC content but 6 hour-ALA incubation reduced it to an undetectable level. BC declined SOD activity and had the ability to delay MDA augmentation in cells which were incubated in medium without or with 0.01 mM ALA. We suppose that soybean oil supplementation decreased GSHPx and catalase activities by higher polyunsaturated fatty acids ratio within the cell which might increase susceptible to free radicals attack and promote prostagladin synthesis. Under oxidative stress, BC had prooxidant property to lower SOD activity, and speed up MDA accumulation in cells incubated in 0.1 mM ALA medium. We conclude that in this experimental model, soybean oil supplementation promotes lipid peroxidation and decreases GSHPx activity by increasing cell susceptible o free radicals. Effect of -carotene on lipid peroxidation and SOD activity is dependent on it’s antioxidative ability.