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In vitro toxicity of hydrogen peroxide against normal vs. tumor rat hepatocytes: Role of catalase and of the glutathione redox cycle
Author(s) -
Mavier Philippe,
Guigui Bernard,
Preaux AnneMarie,
Rosenbaum Jean,
Lescs MarieClaude,
Zafrani Elie Serge,
Dhumeaux Daniel
Publication year - 1988
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840080634
Subject(s) - lactate dehydrogenase , toxicity , catalase , hydrogen peroxide , glucose oxidase , hepatocyte , lysis , biochemistry , oxidase test , chemistry , glutathione , incubation , metabolism , microbiology and biotechnology , enzyme , in vitro , biology , organic chemistry
Hydrogen peroxide produced by stimulated phagocytic cells or during the metabolism of drugs, is toxic to various cell types. The aim of this study was to investigate its toxicity against normal vs. tumor rat hepatocytes. Isolated normal hepatocytes and tumor hepatocytes from three hepatocarcinoma cell lines, Fao, C 2 (Faof1 C 2 ) and HTC, were incubated in the presence of a H 2 O 2 ‐generating system consisting of glucose and varied concentrations of glucose oxidase. The toxicity of H 2 O 2 was quantified by measuring the percentage of lactate dehydrogenase activity released in the culture medium after various times of incubation. By comparison to normal hepatocytes, tumor hepatocytes exhibited an increased susceptibility to lysis by H 2 O 2 . At a concentration of 100 mU per ml, glucose oxidase induced a lactate dehydrogenase activity release of only 6.1 ± 2.2% (mean ± S.E.) from normal hepatocytes and of 71.0 ± 2.9, 45.5 ± 2.5 and 34.7 ± 3.4% from Fao, C 2 and HTC cells, respectively, after an 18‐hr incubation. At a concentration of 10 mU per ml, glucose oxidase had no toxic effect to normal hepatocytes or HTC cells, whereas it induced a lactate dehydrogenase activity release of 58.7 ± 7.6 and 51.2 ± 5.6% from Fao and C 2 cells, respectively. In addition, the time courses of lactate dehydrogenase activity release, studied with 500 mU per ml glucose oxidase, demonstrated that Fao cells, C 2 cells and, to a lesser degree, HTC cells were lysed more rapidly than normal hepatocytes. The toxicity of glucose oxidase was suppressed by the addition of catalase, indicating that it was actually mediated by H 2 O 2 . Catalase activity expressed per cell number and the components of the glutathione redox cycle were decreased in tumor cells by comparison to normal hepatocytes. In addition, treatment of normal hepatocytes with aminotriazole, an inhibitor of catalase, and with 1,3‐bis(2‐chloroethyl)‐1‐nitrosourea, an inhibitor of glutathione reductase, rendered these cells as susceptible as tumor hepatocytes to the effects of H 2 O 2 . In conclusion, tumor hepatocytes were more susceptible to the toxic effect of H 2 O 2 than normal hepatocytes. This difference is probably due to a decrease in the H 2 O 2 detoxication systems that we studied, i.e. catalase and glutathione redox cycle, in tumor cells.