title: Sensitivity of myofibroblasts to H2O2-mediated apoptosis and their antioxidant cell network.
abstract: During wound healing, the transition from granulation to scar tissue shows a decrease in myofibroblast cellularity. Previous results have correlated the disappearance of these cells with the induction of apoptotic cell death by some unknown stimuli. In contrast, hypertrophic scar appearance after wound healing is thought to be linked to a disorder of apoptotic function which induces myofibroblast persistence in granulation tissue. Oxidative stress being an important mediator of apoptosis, we have evaluated the apoptotic response of normal and pathological wound myofibroblasts (WMyo and HMyo respectively) in their interaction with two oxidative stress inducers: hydrogen peroxide, using a high concentration as a single dose, and sodium ascorbate which induced a continuous release of H2O2 at a low concentration. Our results showed that, according to the H2O2 treatment type, HMyo were more sensitive (after ascorbate treatment) or less sensitive (after H2O2 treatment) when compared to WMyo and Fb. We next assessed the presence of several molecules known to be involved in the antioxidant network protecting cells against H2O2 injury and found HMyo to have a higher level of activity of glutathione peroxidase and a lower level of activity of catalase than WMyo. These results can help explain the contradictory responses of myofibroblasts according to the oxidative stress treatment. This is the first study linking refractory oxidative stress mediated cell death to cellular phenotype in hypertrophic myofibroblasts, and indicates a pivotal role for the antioxidant enzyme system in this type of resistance.
authors.affiliation: Laboratoire des grands brûlés/LOEX, Hôpital du Saint-Sacrement du Centre Hospitalier Affilié Universit de Québec, 1050 chemin Sainte-Foy, Québec, Canada.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Larochelle
authors.forename: Céline
authors.initials: C
authors.lastname: Langlois
authors.forename: Isabelle
authors.initials: I
authors.lastname: Thibault
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Lopez-Vallé
authors.forename: Michel
authors.initials: M
authors.lastname: Roy
authors.forename: Véronique
authors.initials: V
authors.lastname: Moulin
mesh_terms: D000328:Adult; D017304:Annexin A5 / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects*; D001205:Ascorbic Acid / Q000378:metabolism / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000473:pathology / Q000502:physiology*; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D005978:Glutathione / Q000032:analysis; D005979:Glutathione Peroxidase / Q000032:analysis; D005980:Glutathione Reductase / Q000032:analysis; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D016877:Oxidants / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D011419:Propidium; D012867:Skin / Q000166:cytology; D013194:Staining and Labeling; D014945:Wound Healing
chemical_list: D017304:Annexin A5; D000975:Antioxidants; D005456:Fluorescent Dyes; D016877:Oxidants; D011419:Propidium; D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D020169:Caspases; D005978:Glutathione; D016650:Fluorescein-5-isothiocyanate; D001205:Ascorbic Acid