The effect of H2O2 and tertiary butyl hydroperoxide upon a murine immortal lens epithelial cell line, αTN4-1

The effect of comparable concentrations of H2O2 and tertiary butyl hydroperoxide (TBHP) upon an immortal murine lens epithelial cell line was examined as part of an ongoing effort to delineate differences in the mechanism by which these peroxides cause cell death. Both compounds result in cell death of normal, unconditioned cells within 24 hr. It was found that with similar conditions, TBHP conditioned alphaTN4-1 cells survive H2O2 stress while H2O2 conditioned cells are killed by TBHP. To better understand how these peroxides act, their effect upon un-conditioned cells has been investigated. Both peroxides cause a rapid loss of GSH and disruption of pump activity as illustrated by C-14-choline transport and Rb-86 uptake. While H2O2 exposure resulted in extensive DNA damage, TBHP had a minimal effect. DNA damage caused by H2O2 was shown to activate polyADP-ribosyl polymerase (PARP), leading to depletion of NAD and ATP. H2O2 induced cell death could be delayed by addition of 3-aminobenzamide (3AB), an inhibitor of PARP. AtP levels in cells subjected to H2O2 were also maintained by the presence of 3AB. H2O2 stress also disrupted glycolysis and mitochondrial activity but these parameters were not affected by TBHP. TBHP induced cell death, under the relatively mild conditions used in this work, appears to be caused by membrane disruption and loss of a reducing environment. (C) 2002 Published by Elsevier Science Ltd.