2005 Fiscal Year Final Research Report Summary
Nutritional approach to the evaluation of oxidative stress and to its prevention by diets
| Project/Area Number |
14208010
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
食生活
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| Research Institution | Nara Women's University |
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Principal Investigator |
KOJO Shosuke Nara Women's University, Faculty of Human Life and Environment, Professor, 生活環境学部, 教授 (10108988)
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| Co-Investigator(Kenkyū-buntansha) |
ICHI Ikuyo Nara Women's University, Faculty of Human Life and Environment, Research Associate, 生活環境学部, 助手 (50403316)
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| Project Period (FY) |
2002 – 2005
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| Keywords | Oxidative stress / Reactive oxygen species / Atherosclerosis / Vitamin C / Vitamin E / Cell death / MAPK / Low-density lipoprotein |
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| Research Abstract |
1.Oxidative stress in vivo was evaluated based on indices such as vitamin C (ASC), vitamin E, and lipid hydroperoxide. In the brain of senescence-accelerated mice, lipid hydroperoxide was found to reflect the ageing process. Using hepatitis model caused by chemicals, vitamin C was found to be the most sensitive index of oxidative stress.
2.The biological activity of L-dehydroascorbic acid (DHA) has long been considered to be equivalent to ASC. We reevaluated the nutritional activity of orally ingested DHA by comparing ASC concentrations in 12 tissues of rats administered four different doses of ASC. Determinations were made by the specific and sensitive method developed by us. We showed that the efficiency of DHA was almost 10% of ASC on the molar basis, based on animal experiments using the inherently scorbutic ODS rat. Based on these findings, we propose that it is necessary to reevaluate the nutritional requirement of ASC based on both ASC and DHA contents of foods.
3.We established that radical reaction of low density lipoprotein (LDL) causes fragmentation and cross-linkage of apolipoprotein B-100 (apoB). We demonstrated that fragmented and cross-linked apoB proteins are present in normal human serum and increase with age based on immunoblot analysis. In addition, a method was developed to evaluate the fragmentation and conjugation pattern of apoB. A parameter named B-ox was introduced for each serum sample to quantitate the staining bands of the immunoblotting analysis. B-ox represents the abundance of radical reaction products (a sum of fragmented and conjugated apoB proteins). Based on measurements of human subjects, B-ox showed significant positive correlation with intima-media thickness (IMT) of the carotid artery, LDL cholesterol, and age, while it showed significant negative correlation with high density lipoprotein cholesterol and ASC. These results suggest that B-ox is a reliable indicator of atherosclerosis.
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