title: Benzoyl peroxide cytotoxicity evaluated in vitro with the human keratinocyte cell line, RHEK-1.
abstract: The human keratinocyte cell line, RHEK-1, was used to evaluate the cytotoxicity of benzoyl peroxide (BZP). As determined with the neutral red (NR) cytotoxicity assay, the 24-h midpoint (NR50) toxicity values, in mM, were 0.11 for BZP and 29.5 for benzoic acid, the stable metabolite of BZP. Irreversible cytotoxicity occurred after a 1-h exposure to 0.15 mM BZP and greater. When exposed to BZP for 7 days, a lag in growth kinetics was first observed at 0.06 mM BZP. Damage to the integrity of the plasma membrane was evident, as leakage of lactic acid dehydrogenase occurred during a 4-h exposure to BZP at 0.05 mM and greater. Intracellular membranes were also affected, as extensive vacuolization, initially perinuclear but then spreading throughout the cytoplasm, was noted in BZP-stressed cells. The generation of reactive free radicals from BZP was suggested by the following: the intracellular content of glutathione was lowered in cells exposed to BZP; cells pretreated with the glutathione-depleting agent, chlorodinitrobenzene, were hypersensitive to a subsequent challenge with BZP; lipid peroxidation by BZP was inducible in the presence of Fe2+; and cells previously maintained in a medium amended with vitamin E, an antioxidant, were more resistant to BZP, showed less lipid peroxidation in the presence of BZP+Fe2+ and did not develop the extensive intracellular vacuolization as compared to non-vitamin E maintained cells.
authors.affiliation: Department of Biology, Stern College for Women, Yeshiva University, New York, NY 10016, USA.
authors.forename: H
authors.initials: H
authors.lastname: Babich
authors.forename: H L
authors.initials: HL
authors.lastname: Zuckerbraun
authors.forename: B J
authors.initials: BJ
authors.lastname: Wurzburger
authors.forename: Y L
authors.initials: YL
authors.lastname: Rubin
authors.forename: E
authors.initials: E
authors.lastname: Borenfreund
authors.forename: L
authors.initials: L
authors.lastname: Blau
mesh_terms: D001555:Benzene Derivatives / Q000633:toxicity; D001585:Benzoyl Peroxide / Q000633:toxicity*; D016923:Cell Death / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000648:ultrastructure; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007641:Keratolytic Agents / Q000633:toxicity*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D009499:Neutral Red; D010545:Peroxides / Q000633:toxicity; D014617:Vacuoles / Q000187:drug effects / Q000648:ultrastructure; D014810:Vitamin E / Q000494:pharmacology; D020122:tert-Butylhydroperoxide
chemical_list: D001555:Benzene Derivatives; D007641:Keratolytic Agents; D010545:Peroxides; D014810:Vitamin E; D009499:Neutral Red; D004247:DNA; D020122:tert-Butylhydroperoxide; D007770:L-Lactate Dehydrogenase; D005978:Glutathione; C007164:cumene hydroperoxide; D001585:Benzoyl Peroxide