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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #164744
Title: VITAMIN C AND VITAMIN E RESTORE THE RESISTANCE OF GSH-DEPLETED CELLS TO H2O2

Author
item SHANG, FU - TUFTS-HNRCA
item LU, MINYI - TUFTS-HNRCA
item DUDEK, EDWARD - TUFTS-HNRCA
item REDDAN, JOHN - OAKLAND UNIVERSITY
item TAYLOR, ALEEN - TUFTS-HNRCA

Submitted to: Free Radical Biology and Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2002
Publication Date: 3/1/2003
Citation: Shang, F., Lu, M., Dudek, E., Reddan, J., Taylor, A. 2003. Vitamin c and vitamin e restore the resistance of gsh-depleted cells to h2o2. Free Radical Biology And Medicine. 34(5):521-530.

Interpretive Summary: A decline in reduced glutathione levels is associated with aging and many age-related diseases. The objective of this study was to determine whether other antioxidants can compensate for glutathione depletion in protecting against oxidative damage. Rabbit lens epithelial cells were depleted of greater than 75% of intracellular glutathione by buthionine sulfoximine. Depletion of glutathione by buthionine sulfoximine alone had little direct effect on cell viability, but resulted in an increase in susceptibility to hydrogen peroxide induced cell death. Cells that were pretreated with antioxidant vitamins C and E, restored the resistance of glutathione depleted cells to hydrogen peroxide. However, concentrations of vitamin C greater than 400 micrometer and vitamin E greater than 80 micrometers enhanced the toxic effect of hydrogen peroxide. The ability of vitamins C and E in compensations for glutathione depletion to protect against hydrogen peroxide induced cell death suggests that glutathione, vitamins C and E have common targets in their actions against oxidative damage, and supports the preventive or therapeutic use of these vitamins to combat age and pathology associated declines in glutathione. Levels of these nutrients must be optimized in cells to achieve the maximum benefit.

Technical Abstract: A decline in reduced glutathione (GSH) levels is associated with aging and many age-related diseases. The objective of this study was to determine whether other antioxidants can compensate for GSH depletion in protection against oxidative insults. Rabbit lens epithelial cells were depleted of > 75% of intracellular GSH by 25-200 microM buthionine sulfoximine (BSO). Depletion of GSH by BSO alone had little direct effect on cell viability, but resulted in an approximately 30-fold increase in susceptibility to H(2)O(2)-induced cell death. Experimentally enhanced levels of nonprotein sulfhydryls other than GSH (i.e., N-acetylcysteine) did not protect GSH-depleted cells from H(2)O(2)-induced cell death. In contrast, pretreatment of cells with vitamin C (25-50 microM) or vitamin E (5-40 microM), restored the resistance of GSH-depleted cells to H(2)O(2). However, concentrations of vitamin C > 400 microM and vitamin E > 80 microM enhanced the toxic effect of H(2)O(2). Although levels of GSH actually decreased by 10-20% in cells supplemented with vitamin C or vitamin E, the protective effects of vitamin C and vitamin E on BSO-treated cells were associated with significant ( approximately 70%) decreases in oxidized glutathione (GSSG) and concomitant restoration of the cellular redox status (as indicated by GSH:GSSG ratio) to levels detected in cells not treated with BSO. These results demonstrate a role for vitamin C and vitamin E in maintaining glutathione in its reduced form. The ability of vitamin C and vitamin E in compensations for GSH depletion to protect against H(2)O(2)-induced cell death suggests that GSH, vitamin C, and vitamin E have common targets in their actions against oxidative damage, and supports the preventive or therapeutic use of vitamin C and E to combat age- and pathology-associated declines in GSH. Moreover, levels of these nutrients must be optimized to achieve the maximal benefit.