EFFECTS OF VITAMIN-E, VITAMIN-C AND CATALASE ON BROMOBENZENE-INDUCED AND HYDROGEN-PEROXIDE-INDUCED INTRACELLULAR OXIDATION AND DNA SINGLE-STRAND BREAKAGE IN HEP G(2) CELLS

Citation
J. Wu et al., EFFECTS OF VITAMIN-E, VITAMIN-C AND CATALASE ON BROMOBENZENE-INDUCED AND HYDROGEN-PEROXIDE-INDUCED INTRACELLULAR OXIDATION AND DNA SINGLE-STRAND BREAKAGE IN HEP G(2) CELLS, Journal of hepatology, 26(3), 1997, pp. 669-677
Citations number
32
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Gastroenterology & Hepatology
Journal title
ISSN journal
0168-8278
Volume
26
Issue
3
Year of publication
1997
Pages
669 - 677
Database
ISI
SICI code
0168-8278(1997)26:3<669:EOVVAC>2.0.ZU;2-M
Abstract
Background/Aims: Water-soluble vitamin E (Trolox C), ascorbic acid and catalase were shown in our previous study to protect isolated rat hep atocytes against bromobenzene-induced toxicity. Methods: In order to s tudy the mechanisms of this protection and the pathogenesis of bromobe nzene-induced hepatocellular injury, a fluorometric assay for the inve stigation of intracellular oxidation, indicated by conversion of dichl orofluorescein diacetate to dichlorofluorescein, was used, Single-stra nd DNA breakage was also evaluated in Hep G(2) cells by a radio-labell ing method. Results: Bromobenzene (2.4 and 4.8 mM) induced a significa nt increase in dichlorofluorescein fluorescence intensity compared to the controls, Trolox C, ascorbic acid or catalase significantly inhibi ted bromobenzene-induced enhancement of fluorescence intensity (p<0.05 -0.001), as well as reduced auto-intracellular oxidation in untreated Hep G(2) cells, Hydrogen peroxide (H2O2) evoked a dose-dependent incre ase in dichlorofluorescein fluorescence intensity in Hep G(2) cells, a nd the effect was completely blocked by Trolox C (2.0 mM) and catalase (4800 unit/ml), Bromobenzene caused significant single-strand DNA bre akage in Hep G(2) cells during 2 h suspension incubation and 24 h prim ary incubation, H2O2 (400 mu M) led to marked single-strand DNA breaka ge in 20 min, and the effect was attenuated by Trolox C, Conclusions: Metabolism of bromobenzene in Hep G2 cells induces production of H2O2, indicated by enhancement of dichlorofluorescein fluorescence intensit y, or other free radicals, which leads to single-strand DNA breakage i n the cells, Vitamins E and C and catalase display strong intracellula r antioxidative effects, Vitamin E could partially inhibit H2O2-induce d single-strand DNA breakage in the cells.