| Summary: | 碩士 === 中山醫學院 === 營養科學研究所 === 85 === Drug metabolism and normal metabolism in cellular
microenvirement can lead to the production of reactive oxygen
species. Once these reactive these reactive oxygen species
cannot be eliminated, cells will be damaged and leads to
membrane morphological changes, such as the bleb formation.
Tocopherol, the important antioxidant molecule of cell membrane,
can protect membrane lipids and proteins from oxidative damage.
Besides, other intracellular antioxidants, such as glutathione
(GSH), is also known to have similar functions as tocopherol.
Therefore, in this study, we compare the protective effects of
tocopherol and GSH on the cell morphology in rat hepatocytes
under oxidative stress. In the first section of this study, by
treating cells with tert-butyl hydroperoxides, we examined the
effects of tocopherol and GSH on lipid peroxidation, membrane
protein thiol depletion, cytoskeleton, and cell blebbing.
Results indicated that cell morphological change was not
directly related to lipid peroxidation, but was corresponded to
membrane protein thiol status. Tocopherol suppresses blebbing
formation, however, the effect of glutathione is not
significant. In the second part, we further examined the role of
intracellular thiol status (including non-protein and protein
thiols) on cell blebbing. In this study, hepatocytes were
pretreated with L-buthionine sulfoximine following by a thiol
oxidizing agent, diamide. Result indicated that protein thiols
play a more important role on protecting cell from morphological
change than GSH. In conclusions: 1). Lipid peroxidation is not
an essential of blebbing formation in hepatocytes, otherwise,
membrane protein oxidation may play a more important role. 2).
Tocopherol effectively inhibits the polymerization of actin, the
depletion of membrane protein thiol, and the morphological
changes. However, the protection of GSH on these parameters is
less significant than tocopherol is. 3). The oxidation of actin
thiols is related to the change of cell morphology.
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