ABSTRACT
We previously reported that dietary vitamin E deficiency increased anxiety-like behaviour in rats exposed to social isolation. Here, we performed a detailed investigation of this phenomenon and its underlying mechanism. First, we fed Wistar rats with a vitamin E-free diet for 3 d, 1 week or 2 weeks and found an increase in anxiety-like behaviour after 1 and 2 weeks of vitamin E deficiency based on behavioural indicators. Next, we examined the effect of a control diet (150 mg all-racemic α-tocopheryl acetate/kg) on anxiety-like behaviours in rats that received a 4-week vitamin E-free diet. We found that increased anxiety-like behaviour was reversed to control levels after refeeding vitamin E for 7 d but not for 1 or 3 d. Further, anxiety-like behaviour increased or decreased gradually based on the amount of vitamin E intake; however, it had a quicker progression than physical symptoms of vitamin E deficiency. Moreover, rats fed with excess vitamin E (500 mg all-racemic α-tocopherol/kg diet) showed less anxiety-like behaviour than control rats, indicating that vitamin E supplementation is effective for preventing anxiety increase under social isolation stress. Since plasma corticosterone levels were higher in vitamin E-deficient rats, we investigated the effect of adrenalectomy on anxiety-like behaviour and found that adrenal hormones played an essential role in the increased anxiety-like behaviour induced by vitamin E deficiency. In conclusion, increased anxiety-like behaviour is a symptom that emerges earlier than physical vitamin E deficiency and is caused by adrenal hormone-dependent mechanisms.
Subject(s)
Adrenalectomy , Anxiety/etiology , Behavior, Animal , Vitamin E Deficiency/psychology , Vitamin E/administration & dosage , Animals , Anxiety/surgery , Diet/adverse effects , Diet/methods , Dietary Supplements , Rats , Rats, Wistar , Vitamin E Deficiency/etiology , Vitamin E Deficiency/surgery , alpha-Tocopherol/administration & dosageABSTRACT
Alpha-tocopherol (vitamin E) is a plant-derived antioxidant that is essential for human health. Studies with humans and with animal models of vitamin E deficiency established the critical roles of the vitamin in protecting the central nervous system, and especially the cerebellum, from oxidative damage and motor coordination deficits. We review here the established roles of vitamin E in protecting cerebellar functions, as well as emerging data demonstrating the critical roles of alpha-tocopherol in preserving learning, memory and emotive responses. We also discuss the importance of vitamin E adequacy in seemingly unrelated neurological disorders.
Subject(s)
Neurodegenerative Diseases/metabolism , Vitamin E/metabolism , Animals , Cognition/physiology , Humans , Neurodegenerative Diseases/psychology , Vitamin E/chemistry , Vitamin E Deficiency/metabolism , Vitamin E Deficiency/psychologyABSTRACT
Oxidative stress contributes to age-related cognitive decline. In some instances, consumption of fruits and vegetables rich in antioxidant can provide superior protection than supplementation with purified antioxidants. Our prior studies have shown that supplementation with apple juice concentrate (AJC) alleviates oxidative damage and cognitive decline in adult (9-12 months) mice lacking ApoE (as a model of increased oxidative stress) and in normal aged (2-2.5 years) mice when challenged with a vitamin-deficient, oxidative stress-promoting diet. Here, we demonstrate that AJC, administered in drinking water, maintains acetylcholine levels that otherwise decline when adult and aged mice are maintained on the above deficient diet. Normal mice aged either 9-10 months or 2-2.5 years and ApoE-/- mice aged 9-10 months were maintained for 1 month on a complete diet or a diet lacking folate and vitamin E and containing iron as a pro-oxidant, and additional groups received 0.5% AJC ad libitum in drinking water. Spectrophotometric assay of acetylcholine levels revealed a significant decline in homogenates of combined frontal cortex and hippocampus for all mice maintained on the deficient diet, and a prevention of this decline in mice maintained on the deficient diet when supplemented with AJC. These findings provide a likely mechanism by which consumption of antioxidant-rich foods such as apples can prevent the decline in cognitive performance that accompanies dietary and genetic deficiencies and aging.
Subject(s)
Acetylcholine/metabolism , Antioxidants/pharmacology , Beverages , Cognition/physiology , Food Deprivation/physiology , Malus/chemistry , Animals , Apolipoproteins E/genetics , Brain/pathology , Brain Chemistry/drug effects , Diet , Folic Acid Deficiency/psychology , Mice , Mice, Inbred C57BL , Mice, Knockout , Oxidative Stress/drug effects , Vitamin E Deficiency/psychologyABSTRACT
OBJECTIVE: To investigate the reported association between low vitamin E levels and depressive symptoms in a population-based study. METHODS: The study is based on a cohort of 3884 adults aged 60 years and over who participated in the third survey of the Rotterdam Study, were screened for depressive symptoms with the Center of Epidemiological Studies Depression Scale and from whom blood was drawn. All screen-positive subjects had a psychiatric work-up. Blood levels of vitamin E were compared between 262 cases with depressive symptoms and 459 randomly selected reference subjects. All analyses were stratified by sex, and adjusted for age, cholesterol, cognitive score, smoking, dietary supplement use, marital status, living alone, and functional disability score. RESULTS: Vitamin E levels in men with depressive symptoms were lower than in non-depressed men after adjusting for age, whereas no such difference was found in women. This association in men was substantially weakened after controlling for biological factors, and disappeared with additional adjustment for nutritional behaviour and social factors. No differences were observed when the analyses were restricted to cases with depression as defined in the Diagnostic and Statistical Manual of Mental Disorders IV. CONCLUSIONS: After control for several biological and behavioural factors relating to health we found no association between low vitamin E levels and depressive symptoms or depression in the elderly.
Subject(s)
Depression/diagnosis , Vitamin E Deficiency/psychology , Aged , Aged, 80 and over , Antioxidants/administration & dosage , Cholesterol/blood , Chromatography, High Pressure Liquid , Cohort Studies , Depression/blood , Depression/epidemiology , Female , Humans , Male , Middle Aged , Nutritional Status , Oxidative Stress , Sex Factors , Vitamin E Deficiency/bloodABSTRACT
To elucidate the influence of oxidative stress on the brain functions during aging, the cognitive performance ability of rats was assessed by using the water-maze test as an oxidative stress before and after hyperoxia. Young rats showed significantly greater learning ability than both old rats and vitamin-E-deficient rats. Although the memory functions of all rats were Impaired after oxidative stress, the memory retention of young rats was greater than those of other groups. After the stress, none of the rats recovered their learning ability. During aging and through hyperoxia, the release of acetylcholine from nerve terminals was remarkably decreased. Instead, thiobarbituric acid reactive substance (TBARS) contents in rat hippocampus and cebral cortex, and their synaptic membranes, were significantly increased during aging and by oxidative stress. The antioxidative defense system in rat brain was also changed by the stress. These results suggest that oxidative stress may contribute to learning and memory deficits following oxidative brain damage during aging.
