| Summary: | 碩士 === 國立中興大學 === 食品科學系 === 90 === Abstract
There were two parts in this research. In part one we compared the oxidative damage to S.D. rats by different oxidative damage models which have been described and proved to cause oxidative damage in liver and/or kidney in animal model by many investigators and try to select a model which caused oxidative damage both in liver and kidney. These oxidative models are described as follow: (1) I.p injection of Fe/NTA (9 mg Fe/kg b.w.) to rats and killed after 30,60,90,120 minutes. (2) I.p. injection of 2-nitropropane (100mg/
kg b.w.) to rats and killed after 6 or 15 hours. (3) Introduced bromobenzene (9 mmol/kg b.w.) to rats by intragastric, and killed the rats after 17 hours. (4) I.p.
injection of ADP-FeCl2-ascorbic acid (5mg-30mg-170mg/kg b.w.) to rats for 3 days, and killed the rats 24 hours after the last administration. Lipid peroxidation (TBARS), non protein SH groups (NPSH), and DNA damage (8-OHdG) in liver and kidney were determined as marker of oxidative damage.
Results showed that when compare to other oxidative models, i.p injection of Fe/NTA(9 mg Fe/kg b.w.) and killed 120 minutes after the injection caused serious oxidative damage in the rats. This oxidative model significantly increased the lipid peroxidation and 8-OHdG both in liver and kidney, it also significantly decreased the NPSH levels in liver. Since this oxidative model caused serious oxidative damage both in liver and kidney, we used it in the second part research as a sutibule oxidative model.
In part 2 we investigate the effects of 4 kinds flavonoids ( quercetin, rutin, hesperidin, silibinin ) to oxidative damage induced by Fe/NTA. S.D rats were administrated to 4 kinds of flavonoids by intragastric for 1 week (100mg/kg b.w./day), and were followed by Fe/NTA-induced oxidative damage model selected from part 1 (9mg Fe/kg b.w, 120 mins). By the consideration of high content of vit E in general laboratory diet and in order to investigate is there any interaction between vit E and flavonoids in vivo, we used the self-mixed diet, each group sub-divided into two groups and supplied with vit E-deficient diet and vit E-supplemented diet (30 mg α-tocopherol acetate/kg diet). Lipid peroxidation (TBARS), non protein SH groups (NPSH), and DNA damage (8-OHdG,Comet assay) in liver and kidney were determined as marker of oxidative damage.
The result showed that: (1) The chemical structure of flavonoids (such as the number and position of hydroxyl groups) strongly affected their antioxidant/
prooxidant activity in vivo. (2) Some antioxidant/prooxidant activity of flavonoids only found in kidney but not in liver, these results imply that the absorbtion and metabolism are different in liver and kidney. (3)When the flavonoids were co-exist with vit E, the higher antioxidant activity was result.
We also investigated the antioxidant/prooxidant activity of flavonoids on
Fe/NTA-induced DNA damage and lipid peroxidation in HepG2 cell line by
time and dose dependent experiment, and we used this result to compare with
the results in vivo for investigated the correlation between in vivo (S.D rats)
and in vitro (HepG2 cell line) systems.
Results showed that the incubation time and dose both strongly effects the antioxidant/prooxidant activity of flavonoids in HepG2 cell line, and there was no absoult correlation between in vivo (S.D rats) and in vitro (HepG2 cell line) systems. From this results we suggest that a wide range of incubation time and dose is needed for in vitro experiment and there is no absoult correlation between in vivo and in vitro.
Key words: oxidative damage model, Fe/NTA, 2-nitropropane, bromobenzene, ADP-FeCl2-ascorbic acid, flavonoids, quercetin, rutin, hesperidin, silibinin, in vivo and in vitro
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