The effect of vitamin E treatment on oxidative stress generated in trained rats

The effect of endurance training with and without vitamin E on expression of p53 and PTEN tumor suppressing genes in prostate glands of male rats

The aim of this study was to investigate the effect of endurance training with and without vitamin E on the expression of p53 and Phosphatase and tension homolog (PTEN) tumor suppressor genes of prostate glands in male rats. For this purpose, 50 Sprague-Dawley male rats were randomly assigned into 5 groups: (1) control group (CON, n = 10), (2) sham (S, n = 10), (3) endurance training (ET, n = 10), (4) endurance training + vitamin E (ET + VE, n = 10), (5) vitamin E (VE, n = 10). Endurance training protocol was implemented for 6 weeks, 6 days per week, in accordance with the overload principle. To measure expression changes of p53 and PTEN genes in rats' prostate, real-time PCR method was used and HPLC method was used to measure vitamin E in this tissue. After 6 weeks of taking vitamin E, its level in all groups, except for group VE (p < 0.000) did not significantly increase. After implementing training protocol, p53 expression reduced significantly in ET group (p < 0.026). Vitamin E supplementation along with endurance training did not cause any significant change either p53 or PTEN (respectively; p < 0.2, p < 0.11). Instead, vitamin E supplementation without endurance training caused significant increase in PTEN, but did not cause any significant changes in p53 (respectively; p < 0.016, p < 0.15). These results indicate that endurance training reduces p53 and PTEN tumor suppressing genes expression, and taking vitamin E supplement could increase expression of these genes in some extent.

Efficacy of Evolvulus alsinoides (L.) L. on insulin and antioxidants activity in pancreas of streptozotocin induced diabetic rats

AIM

Diabetes mellitus (DM), a leading non communicable disease with multiple etiologies is considered as third greatest cause of death in all over the world. During DM, persistent hyperglycemia causes an increased production of free radicals via auto oxidation of glucose and non-enzymatic protein glycation which may lead to disruption of cellular functions and oxidative damage to membranes. The present study was designed to investigate the therapeutic effect of Evolvulus alsinoides on antioxidant activity in pancreas of experimental diabetes.

METHODS

The antioxidant activities were done by using standard protocols. For histopathological analysis, the pancreatic tissues of all experimental groups were fixed with 10% formalin for 24 hrs then the samples were stained with haemotoxylin-eosin for the microscopic observation.

RESULTS

Oral administration of plant extract for 45 days resulted in significant antioxidant activity, increases the insulin level and also inhibits lipid peroxidation in pancreas of streptozotocin induced diabetic rats. The histopathological studies showed the normal histology of pancreas after treatment with plant extract and glibenclamide. This study showed that the administration of Evolvulus alsinoides to streptozotocin induced diabetic rats improves the antioxidant activity and remodel the structure of pancreas due to the presence of secondary metabolites like phenols, flavonoids, alkaloids, steroids, terpenoids and glycosides in the ethanolic extract of plant material.

CONCLUSION

From the present study, it can be concluded that the plant extract effectively reduced the oxidative stress induced by streptozotocin and potentially increased the insulin level. Hence, it can be used in the management of diabetes mellitus.

Multivitamin-mineral and vitamins (E + C) supplementation modulate chronic unpredictable stress-induced oxidative damage in brain and heart of mice

Brain is a target of stress along with the immune, metabolic, and cardiovascular systems of the body. In the present work, the preventive roles of a multivitamin-mineral supplement and vitamins (E + C) in chronic unpredictable stress (CUS)-induced oxidative damage were studied in the brain and heart of Swiss albino mice. Thirty-two mice were randomized to one of the following groups: control + vehicle, CUS + vehicle, CUS + multivitamin-mineral, and CUS + vitamins (E + C). CUS was applied for 4 weeks, and multivitamin-mineral and vitamins (E + C) were administered orally for the same period. CUS led to a negative impact on all the biochemical parameters analyzed. Elevation in malondialdehyde and reduction in glutathione levels were found. The activities of superoxide dismutase, catalase, glutathione S-transferase, and glutathione reductase were decreased. Treatment with multivitamin-mineral and vitamins (E + C) brought these parameters to near normal levels. Multivitamin-mineral was found more restitutive than combined vitamins (E + C) doses. The present study hypothesizes that supplementation with a multivitamin-mineral may prove more effective than vitamin treatment alone in the alleviation of oxidative damage in brain and heart during periods of chronic stress.

Efeitos da dieta suplementada com ômega-3 no músculo sóleo de ratos submetidos à natação: análise histológica e morfométrica

As lesões musculares têm sido observadas como as mais frequentes nos esportes. Considerando a produção de espécies reativas de oxigênio como um fator de risco para instalação de lesões e características antioxidantes e anti-inflamatórias do ômega-3, o objetivo deste trabalho foi verificar as alterações histológicas e morfométricas do músculo sóleo de ratos que realizaram natação, associado a uma dieta suplementada com ômega-3. Para sua realização foram utilizados 31 ratos Wistar divididos em quatro grupos, sendo os grupos A e C suplementados com azeite de oliva e B e D com 3g/dia de ômega-3 por quatro semanas. Os grupos C e D foram submetidos à natação cinco dias/semana por 28 dias, com acréscimo de 5% do peso corporal a partir da segunda semana, enquanto que os grupos A e B não realizaram treinamento. Após este período os animais foram sacrificados, o músculo sóleo retirado e corado com Hematoxilina-eosina para avaliação morfológica. Análise de variância bifatorial, com nível de significância de 5%, foi utilizada para análise dos valores do menor diâmetro das fibras musculares. Os grupos A e B (sedentários) apresentaram padrões histológicos de normalidade. O grupo C apresentou aumento do tecido endomisial e do número de núcleos, presença de fibras fagocitadas e de contornos poligonais não mantidos, enquanto que o grupo D apresentou poucas fibras fagocitadas e de contornos poligonais preservados. Com relação à medida do menor diâmetro das fibras musculares, as análises mostraram diferenças para o fator treinamento, mas não para o fator suplementação e a interação entre eles. As alterações histológicas induzidas pelo exercício foram atenuadas no grupo suplementado com ômega-3, sugerindo um efeito protetor da suplementação, contudo, o aumento do diâmetro das fibras para os grupos expostos ao exercício está relacionado ao efeito do treinamento e não à suplementação.

Vitamin E prevents buthionine sulfoximine-induced biochemical disorders in the rat

Antioxidant therapy can improve the protection and metabolic activity of cells and tissues. In this study, the effect of vitamin E administration on buthionine sulfoximine (BSO)-induced glutathione (GSH) depletion in the rat lung and liver was investigated. Hepatic GSH was depleted by intraperitoneal administration of BSO (4 mmol kg−1), twice a day, for 30 days to rats. We also investigated whether the lung and liver mitochondrial GSH contents were influenced by BSO administration and whether an extracellular supply of vitamin E could prevent the changes caused by BSO-mediated GSH depletion. Glutathione levels in lung and liver tissues were depleted by 47% and 60%, respectively. Depletion of hepatic and pulmonary GSH in turn causes decline in the levels of mitochondrial GSH, leading to impaired antioxidant defence function of mitochondria. Both the cytosolic and mitochondrial glutathione disulfides (GSSG) were altered during BSO treatment, and led to drastic increase in GSSG/GSH redox status. One of the experimental groups was given vitamin E (65 mg (kg diet)−1) mixed with rat feed. The rats fed with vitamin E were found to have partially restored GSH levels in liver and lung, diminished levels of TBARS and minimized tissue damage. The current findings suggest that the impaired glutathione and glutathione-dependent enzyme status may be correlated with the elevated lipid peroxidation and mitochondrial membrane damage and that vitamin E therapy to the BSO-administered rats prevents the above changes. However, vitamin E did not have any effect on the activity of γ-glutamyl cysteine synthetase (γ-GCS).

Iron and exercise induced alterations in antioxidant status. Protection by dietary milk proteins

Lipid peroxidation stress induced by iron supplementation can contribute to the induction of gut lesions. Intensive sports lead to ischemia reperfusion, which increases free radical production. Athletes frequently use heavy iron supplementation, whose effects are unknown. On the other hand, milk proteins have in vitro antioxidant properties, which could counteract these potential side effects. The main aims of the study were: (1) to demonstrate the effects of combined exercise training (ET) and iron overload on antioxidant status; (2) to assess the protective properties of casein in vivo; (3) to study the mechanisms involved in an in vitro model. Antioxidant status was assessed by measuring the activity of antioxidant enzymes (superoxide dismutase (SOD); glutathione peroxidase (GSH-Px)), and on the onset of aberrant crypts (AC) in colon, which can be induced by lipid peroxidation. At day 30, all ET animals showed an increase in the activity of antioxidant enzymes, in iron concentration in colon mucosa and liver and in the number of AC compared to untrained rats. It was found that Casein's milk protein supplementation significantly reduced these parameters. Additional information on protective effect of casein was provided by measuring the extent of TBARS formation during iron/ascorbate-induced oxidation of liposomes. Free casein and casein bound to iron were found to significantly reduce iron-induced lipid peroxidation. The results of the overall study suggest that Iron supplementation during intensive sport training would decrease anti-oxidant status. Dietary milk protein supplementation could at least partly prevent occurrence of deleterious effects to tissue induced by iron overload.

Effects of antioxidant supplementation on insulin sensitivity, endothelial adhesion molecules, and oxidative stress in normal-weight and overweight young adults

The objective of the study was to determine whether short-term antioxidant (AOX) supplementation affects insulin sensitivity, endothelial adhesion molecule levels, and oxidative stress in overweight young adults. A randomized, double-blind, controlled study tested the effects of AOXs on measures of insulin sensitivity (homeostasis model assessment [HOMA]) and quantitative insulin sensitivity check index), endothelial adhesion molecules (soluble intercellular adhesion molecule-1, vascular adhesion molecule, and endothelial-leukocyte adhesion molecule-1), adiponectin, and oxidative stress (lipid hydroperoxides) in overweight and normal-weight individuals (N = 48, 18-30 years). Participants received either AOX (vitamin E, 800 IU; vitamin C, 500 mg; beta-carotene, 10 mg) or placebo for 8 weeks. The HOMA values were initially higher in the overweight subjects and were lowered with AOX by week 8 (15% reduction, P = .02). Adiponectin increased in both AOX groups. Soluble intercellular adhesion molecule-1 and endothelial-leukocyte adhesion molecule-1 decreased in overweight AOX-treated groups by 6% and 13%, respectively (P < .05). Plasma lipid hydroperoxides were reduced by 0.31 and 0.70 nmol/mL in the normal-weight and overweight AOX-treated groups, respectively, by week 8 (P < .05). Antioxidant supplementation moderately lowers HOMA and endothelial adhesion molecule levels in overweight young adults. A potential mechanism to explain this finding is the reduction in oxidative stress by AOX. Long-term studies are needed to determine whether AOXs are effective in suppressing diabetes or vascular activation over time.

Aspectos atuais sobre estresse oxidativo, exercícios físicos e suplementação

As espécies reativas de oxigênio (ERO) são normalmente produzidas pelo metabolismo corporal. Todavia, ERO apresentam a capacidade de retirar elétrons de outros compostos celulares, sendo capazes de provocar lesões oxidativas em várias moléculas, fato que leva à perda total da função celular. A realização de exercícios físicos aumenta a síntese de ERO, além de promover lesão muscular e inflamação. Após uma sessão de exercícios físicos, inicia-se normalmente a fase de recuperação, quando são observados diversos efeitos positivos à saúde, incluindo o aumento da resistência a novas lesões induzidas ou não por exercícios, fato que é considerado como um processo "adaptativo". Diversos estudos, porém, relatam que essa recuperação não é alcançada por indivíduos que se submetem a exercícios intensos e prolongados, ou, ainda, que possuem elevada freqüência de treinamento. Alternativas nutricionais têm sido muito estudadas, a fim de reduzir os efeitos promovidos pelo exercício extenuante, dentre as quais está a suplementação com vitamina E, vitamina C, creatina e glutamina. Esta revisão tem como objetivo abordar os aspectos atuais envolvendo a formação das ERO, os processos de lesão celular e inflamação, a adaptação aos tipos de exercício aeróbio e anaeróbio e possíveis intervenções nutricionais.

Antioxidant supplementation lowers exercise-induced oxidative stress in young overweight adults

OBJECTIVE

To determine whether antioxidant (AOX) supplementation attenuates post-exercise oxidative stress and contributors to oxidative stress (inflammation, blood lipids) in overweight young adults.

RESEARCH METHODS AND PROCEDURES

This was a randomized, double-blind, controlled study. Overweight (BMI, 33.2 +/- 1.9 kg/m(2)) and comparative normal-weight (BMI, 21.9 +/- 0.5 kg/m(2)) adults 18 to 30 years old (total N = 48) were enrolled. Participants received either daily antioxidant (AOX) treatment (800 IU of vitamin E, 500 mg of vitamin C, 10 mg of beta-carotene) or placebo (PL) for 8 weeks for a total of four groups. All participants completed a standardized 30-minute cycle exercise bout at baseline and 8 weeks. Exercise-induced changes in lipid hydroperoxide (DeltaPEROX), C-reactive protein (DeltaCRP), interleukin-6 (DeltaIL-6), cholesterol subfractions, triglycerides, total AOX status (DeltaTAS), and adiponectin were assessed.

RESULTS

Exercise-induced DeltaPEROX was lower in the overweight-AOX group (0.09 nM/kg per min) compared with PL-treated overweight and normal-weight groups (0.98, 0.53 nM/kg per min) by 8 weeks (p < 0.05). Adiponectin was increased in both overweight and normal-weight AOX groups (22.1% vs. 3.1%; p < 0.05) but reduced in PL groups. DeltaIL-6, Deltatotal cholesterol, and Deltalow-density lipoprotein-cholesterol concentrations during exercise were lower in the AOX-treated groups compared with PL groups (all p < 0.05). After controlling for BMI, the Deltatotal cholesterol, Deltalow-density lipoprotein-cholesterol, Deltaadiponectin, and DeltaTAS explained 59.1% of the variance of the regression model of the DeltaPEROX by 8 weeks (total model R(2) = 0.600; p = 0.015).

DISCUSSION

AOX lowers exercise-induced oxidative stress in overweight adults. Inflammatory and lipid markers may also be attenuated with AOX. Further studies are needed to determine whether AOX may be used in cardiovascular disease prevention in the overweight population.

Persistent Oxidative Stress after Myocardial Infarction Treated by Percutaneous Coronary Intervention

Acute myocardial infarction causing cardiac ischemia is responsible for the majority of cardiac related deaths. Medical interventions that ensure rapid reperfusion, such as percutaneous coronary intervention, are aimed to allow myocardial re-oxygenation. However, this generates reactive oxygen species, resembling ischemia-reperfusion type of injury based on oxidative stress. In the present study we monitored dynamic changes of total serum peroxides, total antioxidant capacity and soluble intercellular adhesion molecule-1 as well as the titer of antibodies against oxidized low-density lipoproteins in the blood during the convalescence period of 32 patients with acute myocardial infarction treated by percutaneous coronary intervention. Samples were taken at admittance and at two hours, four hours, three days and seven days following percutaneous coronary intervention. Total antioxidant capacity dropped to 82% (p < 0.05). The titer of antibodies against oxidized low-density lipoproteins transiently decreased within the first three days, and increased afterwards. The values of serum peroxides and soluble intercellular adhesion molecule-1 increased continuously in respect to the initial levels reaching the maximum at the time of release from hospital. These findings indicate a persistent oxidative stress that might be associated with intravascular inflammation in patients during convalescence and release from hospital.