Induction of apoptosis by superoxide anion and the protective effects of selenium and Vitamin E.

OBJECTIVE: The purpose of this study is to investigate the effect of superoxide anion on the apoptosis of cultured fibroblasts and the protective role of selenium and Vitamin E. METHODS: Cultured fibroblasts (NIH3T3), with or without selenium or vitamin E in the medium, were treated by superoxide anion produced by xanthine/xanthine oxidase reaction system and changes in cell structure and DNA were observed microscopically and electrophoretically. RESULTS: Apoptosis was observed when superoxide anion at a concentration of 5 nmol/L or 10 nmol/L had acted on the fibroblasts for 5-10 h. Selenium and Vitamin E in the medium inhibited the apoptosis significantly when their concentrations reached 1.15 mol/L and 2.3 mol/L respectively. CONCLUSION: Selenium and vitamin E have protective effect against the apoptosis induced by superoxide anion. The effect of selenium is more remarkable than that of vitamin E.

Antioxidant status in persons with and without senile lens changes.

Biochemical evidence on lens culture suggests that antioxidant nutrients can protect lens against peroxidation caused by radiation. A case-control study was carried out on 262 middle aged (45-54) and aged (55-64) subjects. The relationship between biochemical markers of antioxidant status and senile lens changes (including cataract) was examined in 131 subjects with senile lens changes and 131 control subjects with clear lens. Antioxidant status was measured using plasma and erythrocyte glutathione peroxidase, erythrocyte superoxide dismutase and catalase activity and plasma levels of vitamin E and vitamin A. Subjects were grouped by age and sex. The results were as follows: (1) The subjects with lens changes tended to have lower plasma levels of vitamin E and vitamin A, lower activity of several antioxidant enzymes and higher level of MDA. (2) The subjects with senile lens changes had significantly lower erythrocyte glutathione peroxidase level. (3) In the middle-aged group, subjects with senile lens changes were observed to have lower erythrocyte and plasma glutathione peroxidase level than those without senile lens changes. The results suggest that appropriate amount of antioxidant nutrients might be expected to prevent or retard the process of lens changes.

Biochemical and morphological changes in the lenses of selenium and/or vitamin E deficient rats.

The activities of glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), superoxide dismutase (SOD) and the contents of malondialdehyde (MDA) and free radicals were measured, and the morphological changes were observed in the lens of control rats, selenium-deficient (SeD) and/or vitamin E deficient (VED) rats. The activities of GSH-Px in the lens of SeD rats decreased significantly. The GSH-Px activities of lens were positively related to erythrocytes selenium level. There was a free radical at g = 2.0015 in the rat lens of all groups, but the content of free radicals in the lens of SeD group was significantly higher than that of the control group. The free radical content of lens was negatively related to erythrocytes selenium level, as well as the GSH-Px activities in the lens. In vitro, ultraviolet radiation caused the generation of another kind of free radical (g = 2.0097) in the lens of all groups, but the amount of the free radical in the lens of the SeD group was also significantly higher than that of the control group. The activities of SOD and GSSG-R in VED rat lens were significantly decreased. The amount of MDA in the lens of SeD and/or VED rats were significantly increased. The results showed that the decrease of antioxidative capability in the lenses of SeD and/or VED rats accelerated the lipid peroxidation and generation of free radicals. Although only early morphological changes in SeD and/or VED rat lens were observed, it is considered that selenium and vitamin E deficiency may be involved in the occurrence of cataract.