title: Comparative effects of alpha-tocopherol and gamma-tocotrienol against hydrogen peroxide induced apoptosis on primary-cultured astrocytes.
abstract: Oxidative stress is thought to be one of the factors that cause neurodegeneration and that this can be inhibited by antioxidants. Since astrocytes support the survival of central nervous system (CNS) neurons, we compared the effect of alpha-tocopherol and gamma-tocotrienol in minimizing the cytotoxic damage induced by H(2)O(2), a pro-oxidant. Primary astrocyte cultures were pretreated with either alpha-tocopherol or gamma-tocotrienol for 1 h before incubation with 100 microM H(2)O(2) for 24 h. Cell viability was then assessed using the MTS assay while apoptosis was determined using a commercial ELISA kit as well as by fluorescent staining of live and apoptotic cells. The uptake of alpha-tocopherol and gamma-tocotrienol by astrocytes were also determined using HPLC. Results showed that gamma-tocotrienol is toxic at concentrations >200 microM but protects against H(2)O(2) induced cell loss and apoptosis in a dose dependent manner up to 100 microM. alpha-Tocopherol was not cytotoxic in the concentration range tested (up to 750 microM), reduced apoptosis to the same degree as that of gamma-tocotrienol but was less effective in maintaining the viable cell number. Since the uptake of alpha-tocopherol and gamma-tocotrienol by astrocytes is similar, this may reflect the roles of these 2 vitamin E subfamilies in inhibiting apoptosis and stimulating proliferation in astrocytes.
authors.affiliation: Department of Biochemistry, Medical Faculty, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia. musalmah@medic.ukm.my
authors.forename: Musalmah
authors.initials: M
authors.lastname: Mazlan
authors.forename: Then
authors.initials: T
authors.lastname: Sue Mian
authors.forename: Gapor
authors.initials: G
authors.lastname: Mat Top
authors.forename: Wan
authors.initials: W
authors.lastname: Zurinah Wan Ngah
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000975:Antioxidants / Q000378:metabolism / Q000627:therapeutic use / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002839:Chromans / Q000378:metabolism / Q000627:therapeutic use / Q000633:toxicity*; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology; D003603:Cytotoxins / Q000037:antagonists & inhibitors; D004305:Dose-Response Relationship, Drug; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors; D019636:Neurodegenerative Diseases / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000378:metabolism / Q000627:therapeutic use / Q000633:toxicity; D024502:alpha-Tocopherol / Q000378:metabolism / Q000627:therapeutic use / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D002839:Chromans; D003603:Cytotoxins; D014810:Vitamin E; C013649:plastochromanol 8; D006861:Hydrogen Peroxide; D024502:alpha-Tocopherol