The Study of the Possible Regulatory Mechanism of The Metabolism of α-Tocopherol in Mice Fed Conjugated Linoleic Acid and its Isomers

• Main Authors: Chia-Ling Chang, 張嘉玲
• Other Authors: Huey-Mei Shaw
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/45491121180104178465

碩士 === 嘉南藥理科技大學 === 營養與保健科技研究所 === 98 === Conjugated linoleic acid (CLA) refers to a group of positional and geometric isomers of the omega-6 essential fatty acid linoleic acid that with 18 carbon atoms and conjugated double bonds. In nature, cis-9, trans-11 CLA (c9, t11) and trans-10, cis-12 CLA (t10, c12)are the two predominant forms of CLA. Many studies have shown that the CLA possess antioxidant activites, we also found the α-tocopherol levels of plasma, liver and peripheral tissues increased when in mice with fed CLA for four weeks in the previous study. Therefore, in experiment 1 we aimed to determine wether the α-tocopherol status is affected by CLA in short-term feeding. In experiment 2, we further confirm whether the hepatic secretion rates of α-tocopherol and triglyceride are influenced by CLA when mice fed one week and four weeks. Since different CLA isomers show different function in animal, in experiment 3, we would like to clarify the effect of CLA isomers (c9, t11 and t10, c12) on the vitamin E status in mice. Experiment 1: Eighteen seven-week-old C57BL/6J male mice were assigned to three groups : control group (CC, containing 5 % soybean oil), CLA group (CLA, containing 4 % soybean oil + 1 % CLA ), and vitamin E supplemented group (VE, containing 5 % soybean oil + 3750 ppm α-tocopherol, equal in common feed vitamin E content 50 times) The feeding period is 1 wk. Experiment 2 : twenty-six seven-week-old C57BL/6J male mice were divided into control group and the CLA group (the same feed ingredients as exp 1). The hepatic secretion rates of α-tocopherol and triglyceride (TG) were measured with Triton-WR1339 injection after 1 wk or 4wk feeding. Experiment 3 : twenty-eight seven-week-old C57BL/6J male mice were divided into 4 groups：according to the diet for 4 wks. CC group : containing 5 % soybean oil, CLA group : containing 4 % soybean oil + 1 % CLA, c9t11 CLA group : containing 4.5 % soybean oil + 0.5 % cis-9, trans-11 CLA , and t10c12 CLA group : containing 4.5 % soybean oil + 0.5 % trans-10, cis-12 CLA. Results from exp 1 showed that the α-tocopherol levels of liver, kidney and epididymal adipose tissue (EP) in the CLA group were significantly higher than that in the CC group. The α-tocopherol concentrations of liver, kidney, spleen and EP of vitamin E supplementation (VE group) was significantly increased. The α-TTP protein content of liver and plasma α-tocopherol levels showed no significant difference in the three groups, however, CLA significantly decreased the triglyceride levels in plasma and liver. The activities of antioxidative enzymes (CAT, GPx) in liver were decreased by CLA feeding, but didn’t change by Vitamin E supplementation. In experiment 2, the results showed that CLA significantly increased the α-tocopherol secretion rate both in the one week or four weeks feeding groups. In contrast, the triglyceride secretion rate was significantly decreased in CLA group when compared with CC group. Experiment 3: The α-tocopherol levels in plasma and tissue significantly increased in CLA group and t10c12 group. The α-TTP protein contents in liver were also elevated by CLA and t10c12 group. Feeding of c9, t11 CLA showed no influence in those parameter. The activities of antioxidative enzymes (CAT, GPx) in liver were decreased by feeding of mixture, c9, t11 CLA and t10, c12 CLA. In conclusion, CLA increased the VE status in one week feeding. The elevation of α-TTP protein levels and the hepatic secretion rate of α-tocopherol by CLA seems to be the major reasons for alteration of VE status in mice. Moreover, t10, c12 CLA isomers is the most active form in the regulation of VE status.