Autor(es):
Rego, Ana Cristina 
; Santos, Maria Sancha ; Proença, Maria Teresa ; Oliveira, Catarina R.
Data: 1998
Identificador Persistente: http://hdl.handle.net/10316/4858
Origem: Estudo Geral - Universidade de Coimbra
Assunto(s): Cell viability; Neurotoxicity; Retinal cells; Vitamin E acetate; Vitamin E succinate
Descrição
In this study, we analyzed the influence of vitamin E succinate (5-80 [mu]M), supplemented in the culture medium, on the survival of cultured retinal cells. The release of lactate dehydrogenase (LDH) was decreased in the presence of low concentrations (10-20 [mu]M) of vitamin E succinate, whereas high concentrations (80 [mu]M) induced a significant increase (about 2-fold) in the release of LDH, indicating a reduction of plasma membrane integrity. Supplementing with vitamin E succinate (80 [mu]M) greatly enhanced its cellular content, as compared to vitamin E acetate (80 [mu]M), and the membrane order of the retinal cells, as evaluated by the fluorescence anisotropy (r) of TMA-DPH (1-(4-(trimethylammonium)-phenyl)-6-phenylhexa-1,3,5-triene), was not altered. Furthermore, vitamin E succinate was more potent than vitamin E acetate in reducing thiobarbituric acid reactive substances (TBARS) formation upon ascorbate-Fe2+-induced oxidative stress (TBARS formation after cell oxidation decreased by about 15-fold or 1.6 fold, respectively, in the presence of 20 [mu]M vitamin E succinate or 20 [mu]M vitamin E acetate). A decrease in MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) reduction induced by supplementing with vitamin E succinate (80 [mu]M), to 35.99±1.96% as compared to the control, but not by vitamin E acetate (80 [mu]M), suggests that vitamin E succinate may affect the mitochondrial activity. Vitamin E succinate also reduced significantly the ATP:ADP ratio in a dose-dependent manner, indicating that vitamin E succinate-mediated cytotoxic effects involve a decrement of mitochondrial function. http://www.sciencedirect.com/science/article/B6TCN-3TC6XS5-4/1/e0ed559c198b926ab93d379fe6d035be
