Tri-n-butyltin delays the cell death induced by hydrogen peroxide in rat thymocytes

Tri-n-butyltin (TBT), one of environmental pollutants accumulated in mollus ks, at nanomolar concentrations decreases cellular content of glutathione ( GSH), suggesting that TBT increases cell vulnerability to oxidative stress because GSH has a role in catabolizing hydrogen peroxide (H2O2). In order t o examine this possibility, the effect of tri-n-butyltin chloride (TBTCl) o n rat thymocytes suffering from oxidative stress induced by H2O2 was examin ed using a flow cytometer with four fluorescent probes; ethidium bromide, 2 ' ,7 ' -dichlorofluorescin diacetate, 5-chloromethylfluoresecin diacetate and annexin-V-FITC. TBTCl at concentrations ranging from 100 nM to 1 muM at tenuated H2O2-induced decrease in cell viability in a dose-dependent manner . It was unlikely that TBTCl reduced H2O2-induced oxidative stress because TBTCl failed to affect H2O2-induced oxidation of intracellular molecule (2 ' ,7 ' -dichlorofluorescin) and H2O2-induced decrease in cellular content o f GSH. Results suggest that TBTCl may inhibit the pathway of cell death ind uced by H2O2 or that TBTCl may induce a protective substance against the ox idative stress produced by H2O2. (C) 2001 Elsevier Science B.V. All rights reserved.