碩士 / 國立陽明大學 / 生物化學研究所 / 90 / Abstract
Epidemiological and experimental studies suggest that fish oil has beneficial effects with regard to prevent cardiovascular disease. This was attributed mainly to the biological effects of the n-3 polyunsaturated fatty acids (PUFA)-rich fish oil on lowering plasma lipids. However, the mechanisms by which fish oil exerts its effects are not fully understood.
Several lines of evidence suggest that oxidatively modified LDL plays an important role in the development of atherosclerosis. There are conflicting results among studies on the effects of fish oil or n-3 PUFA on LDL oxidizability. The important questions of whether supplementation with fish oil renders redox status more prone to oxidative modification or influence cells’ ability to defend oxidative modification have not yet been conclusively answered. To address these questions, we conducted a study to investigate the biological effect of fish oil on redox status in HepG2 and J774A.1 macrophages.
The results showed that treatment of J774A.1 macrophages with fish oil increased the production of superoxide (.O2-) as well as activities and protein expression of the superoxide dismutase (SOD) in 1 and 3 hr. The production of H2O2 as well as activities and protein expression of catalase and glutathione peroxidase (GPx) were increased with treatment of fish oil for 24 hr in J774A.1 macrophage. On the other hand, treatment of HepG2 cells with fish oil induced a less marked effect on the production of H2O2 and activities of the catalase and GPx in 24hr. In terms of the production of .O2- and activities and protein expression of the SOD had no significant effect. These data indicate that macrophages and hepatocytes appear to respond to fish oil treatment by an adaptive mechanism, namely the induction of antioxidant enzyme to remove the overproduction of free radicals.
Finally, we used apoE-deficient mice as an animal model to assess the role of fish oil in the response of oxidative stress in vivo. Dietary supplementation with fish oil was associated with an induction of antioxidant enzyme activities in mouse liver. On the corn oil diet, apoE-deficient mice developed extensive atherosclerotic lesions. However, less atherosclerotic lesions were seen in mice with fish oil diet. In conclusion, induction of antioxidant defense systems by fish oil render cell to defend oxidative modification. As to antiatherogenic mechanism of fish oil need further studies to delineate.
| Identifer | oai:union.ndltd.org:TW/090YM000107028 |
| Date | January 2002 |
| Creators | 洪子茗 |
| Contributors | An-Na Chiang, 姜安娜 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 0 |
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