title: Importance of hydrogen peroxide in nitrofurantoin-induced cytotoxicity: evidence from an inbred catalase-deficient strain of mice.
abstract: Significant pulmonary toxicity is associated with the use of nitrofurantoin; however, the mechanism of cellular toxicity remains poorly characterized. By using a novel in vitro red blood cell (RBC) chromium 51 cytotoxicity assay, cell injury induced by nitrofurantoin was quantified with normocatalasemic BALB/c RBCs and hypocatalasemic (but otherwise genetically identical) CCN RBCs as target cell populations. Nitrofurantoin at concentrations of 2 x 10(-4) and 4 x 10(-4) mol/L resulted in significant injury to normocatalasemic RBCs with a cytotoxic index (CI) of 21.7% +/- 3.7% and 65.3% +/- 3.7% (p less than 0.05, both comparisons). This injury was substantially increased when nitrofurantoin (2 x 10(-4) and 4 x 10(-4) mol/L was incubated with hypocatalasemic RBCs, resulting in CIs of 59.0% +/- 7.4% and 91.0% +/- 2.0% respectively (p less than 0.05, both comparisons with normocatalasemic RBCs). Direct oxidant-mediated cytotoxicity induced by either H2O2 or the superoxide anion radical (as generated by xanthine-xanthine oxidase) also resulted in more significant injury to hypocatalasemic RBCs than to normocatalasemic RBCs (p less than 0.05, both comparisons). Catalase levels of CCN RBCs were approximately 7% of control BALB/c RBC values; however, the activities of superoxide dismutase and glutathione peroxidase were identical in both populations of RBCs. This model, using genetically defined target cell populations, clearly demonstrates the importance of endogenous catalase in protecting against nitrofurantoin-induced cytotoxicity, suggesting that H2O2 is a critical intermediary in the direct cell injury mediated by the drug.
authors.affiliation: Division of Thoracic Diseases, Mayo Clinic, Rochester, MN 55905.
authors.forename: P J
authors.initials: PJ
authors.lastname: Lyng
authors.forename: D L
authors.initials: DL
authors.lastname: Kachel
authors.forename: W J
authors.initials: WJ
authors.lastname: Martin
mesh_terms: D020642:Acatalasia; D000818:Animals; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D006861:Hydrogen Peroxide / Q000633:toxicity*; D066298:In Vitro Techniques; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D009582:Nitrofurantoin / Q000633:toxicity*; D009996:Osmotic Fragility; D010084:Oxidation-Reduction
chemical_list: D009582:Nitrofurantoin; D006861:Hydrogen Peroxide