title: Vitamin E prevents cell death induced by mild oxidative stress in chicken skeletal muscle cells.
abstract: Apoptosis and necrosis are two forms of cell death that can occur in response to various agents and oxidative damage. In addition to necrosis, apoptosis contributes to muscle fiber loss in various muscular dystrophies as well participates in the exudative diathesis in chicken, pathology caused by dietary deficiency of vitamin E and selenium, which affects muscle tissue. We have used chicken skeletal muscle cells and bovine fibroblasts to study molecular events involved in the cell death induced by oxidative stress and apoptotic agents. The effect of vitamin E on cell death induced by oxidants was also investigated. Treatment of cells with anti-Fas antibody (50 to 400 ng/mL), staurosporine (0.1 to 100 microM) and TNF-alpha (10 and 50 ng/mL) resulted in a little loss of Trypan blue exclusion ability. Those stimuli conducted cells to apoptosis detected by an enhancement in caspase activity upon fluorogenic substrates but this activity was not fully blocked by the caspase inhibitor Z-VAD-fmk. Oxidative stress induced by menadione (10, 100 and 250 muM) promoted a significant reduction in cell viability (10%, 20% and 35% for fibroblasts; 20%, 30% and 75% for muscle cells, respectively) and caused an increase in caspase activity and DNA fragmentation. H2O2 also promoted apoptosis verified by caspase activation and DNA fragmentation, but in higher doses induced necrosis. Vitamin E protected cells from death induced by low doses of oxidants. Although it was ineffective in reducing caspase activity in fibroblasts, this vitamin diminished the enzyme activity in muscle cells. These data suggested that oxidative stress could activate apoptotic mechanisms; however the mode of cell death will depend on the intensity and duration of the stimulus, and on the antioxidant status of the cells.
authors.affiliation: Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, Rua Tres de Maio, 100, 6. andar, P.O. Box O4044-020, Sao Paulo, SP, Brazil. vanunes@ib.usp.br
authors.forename: Viviane A
authors.initials: VA
authors.lastname: Nunes
authors.forename: Andrezza J
authors.initials: AJ
authors.lastname: Gozzo
authors.forename: Ilana
authors.initials: I
authors.lastname: Cruz-Silva
authors.forename: Maria A
authors.initials: MA
authors.lastname: Juliano
authors.forename: Tania A
authors.initials: TA
authors.lastname: Viel
authors.forename: Rosely O
authors.initials: RO
authors.lastname: Godinho
authors.forename: Flavio V
authors.initials: FV
authors.lastname: Meirelles
authors.forename: Misako U
authors.initials: MU
authors.lastname: Sampaio
authors.forename: Claudio A M
authors.initials: CA
authors.lastname: Sampaio
authors.forename: Mariana S
authors.initials: MS
authors.lastname: Araujo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D002642:Chick Embryo; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D009336:Necrosis / Q000517:prevention & control; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014810:Vitamin E / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein
chemical_list: D016877:Oxidants; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein; D014810:Vitamin E