Martine Elisabeth Kienzle Hagen

Total antioxidant capacity is impaired in different structures from aged rat brain

Our data support a disproportion between free radicals levels and scavenging systems activity in different cerebral regions of the aging rat. We investigated the total reactive antioxidant potential and reactivity levels, which represent the total antioxidant capacity, in different cerebral regions of the aging rat (cortex, striatum, hippocampus and the cerebellum). In addition, we have determined several oxidative stress parameters, specifically the free radicals levels, the macromolecules damage (lipid peroxidation and carbonyl content), as well as the antioxidant enzymes activities in different cerebral areas from young (2 months‐old), mature adult (6 months‐old) and old (24 months‐old) male Wistar rats. Free radicals levels, determined by 2′,7′‐dichlorofluorescein diacetate probe, were higher in striatum, cerebellum and hippocampus from aged rats. There was an age‐related increase in lipoperoxidation in hippocampus and cerebral cortex. In the cerebellum, a high activity of superoxide dismutase and a decrease of catalase activity were observed. The striatum exhibited a significant catalase activity decrease; and glutathione peroxidase activity was diminished in the hippocampus of mature and aged rats. There was a marked decrease of total antioxidant capacity in hippocampus in both reactivity and potential levels, whereas striatum and cerebral cortex displayed a reduction on reactivity assay. We suggest that age‐related variations of total antioxidant defenses in brain may predispose structures to oxidative stress‐related neurodegenerative disorders.

Glutaric acid induces oxidative stress in brain of young rats.

This study investigated the effects of glutaric acid, which predominantly accumulates in glutaric acidemia type I, on some in vitro parameters of oxidative stress in brain of young rats. We evaluated chemiluminescence, total radical-antioxidant potential (TRAP) and the activities of the antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase in brain tissue homogenates in the presence of glutaric acid at concentrations ranging from 0.05 to 2.0 mM. The acid significantly increased chemiluminescence (up to 65%) and reduced total radical-antioxidant potential (up to 28%) and glutathione peroxidase activity (up to 46%), without affecting catalase and superoxide dismutase activities. The results provide evidence that glutaric acid induces oxidative stress in vitro in rat brain. If these findings also occur in humans, it is possible that they may contribute to the neuropathology of patients affected by glutaric acidemia type I.

Experimental hyperphenylalaninemia provokes oxidative stress in rat brain

Tissue accumulation of L-phenylalanine (Phe) is the biochemical hallmark of human phenylketonuria (PKU), an inherited metabolic disorder clinically characterized by mental retardation and other neurological features. The mechanisms of brain damage observed in this disorder are poorly understood. In the present study we investigated some oxidative stress parameters in the brain of rats with experimental hyperphenylalaninemia. Chemiluminescence, total radical-trapping antioxidant potential (TRAP), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were measured in the brain of the animals. We observed that chemiluminescence is increased and TRAP is reduced in the brain of hyperphenylalaninemic rats. Similar data were obtained in the in vitro experiments using Phe at various concentrations. CAT activity was significantly inhibited by Phe in vitro and in vivo, whereas GSH-Px activity was reduced in vivo but not in vitro and SOD activity was not altered by any treatment. The results indicate that oxidative stress may be involved in the neuropathology of PKU. However, further studies are necessary to confirm and extend our findings to the human condition and also to determine whether an antioxidant therapy may be of benefit to these patients.

In vitro stimulation of oxidative stress in cerebral cortex of rats by the guanidino compounds accumulating in hyperargininemia

Hyperargininemia is a metabolic disorder biochemically characterized by tissue accumulation of arginine and other guanidino compounds. Convulsions, lethargy and psychomotor delay or cognitive deterioration are predominant clinical features of this disease. Although neurologic symptoms predominate in this disorder, their pathophysiology is still unknown. In the present study we investigated the in vitro effects of arginine, N-acetylarginine, argininic acid and homoarginine on some oxidative stress parameters in rat brain in the hope to identify a possible mechanism for the brain damage in hyperargininemia. Chemiluminescence, total radical-trapping antioxidant potential (TRAP), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were measured in the cerebral cortex of rats in the presence of various concentrations of these compounds. The results showed that all guanidino compounds tested significantly increased chemiluminescence and decreased TRAP at concentrations similar to those observed in the tissue of hyperargininemic patients. Furthermore, these compounds inhibited CAT and GSH-Px activities to varying extents, with GSH-Px activity being more susceptible to their action. In turn, argininic acid inhibited all enzyme activities, and its main action was also directed towards GSH-Px. The results suggest that oxidative stress caused by guanidino compounds may be involved in the brain dysfunction amongst other potential pathophysiological mechanisms observed in hyperargininemia.

Effect of cooking on the concentration of bioactive compounds in broccoli (Brassica oleracea var. Avenger) and cauliflower (Brassica oleracea var. Alphina F1) grown in an organic system.

Brassica vegetables have been shown to have antioxidant capacities due to the presence of carotenoids, flavonoids and vitamins. This study evaluates the influence of different processing conditions (boiling, steaming, microwaving and sous vide) on the stability of flavonoids, carotenoids and vitamin A in broccoli and cauliflower inflorescences grown in an organic system. Results indicated that sous vide processing resulted in greater antioxidant capacity and that all processes contributed in some way to an increased content of antioxidant compounds in both cauliflower and broccoli.

Monosialoganglioside Increases Catalase Activity in Cerebral Cortex of Rats

Monosialoganglioside (GM1) is a neuroprotective agent that has been reported to scavenge free radicals generated during reperfusion and to protect receptors and enzymes from oxidative damage. However, only a few studies have attempted to investigate the effects of GM1 on enzymatic antioxidant defenses of the brain. In the present study, we evaluate the effects of the systemic administration of GM1 on the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), and on spontaneous chemiluminescence and total radical-trapping potential (TRAP) in cerebral cortex of rats ex vivo. The effects of GM1 on CAT activity and spontaneous chemiluminescence in vitro were also determined. Animals received two injections of GM1 (50 mg/kg, i.p.) or saline (0.85% NaCl, i.p.) spaced 24 h apart. Thirty minutes after the second injection the animals were sacrificed and enzyme activities and spontaneous chemiluminescence and TRAP were measured in cell-free homogenates. GM1 administration reduced spontaneous chemiluminescence and increased catalase activity ex vivo, but had no effect on TRAP, SOD or GSH-Px activities. GM1, at high concentrations, reduced CAT activity in vitro. We suggest that the antioxidant activity of GM1 ganglioside in the cerebral cortex may be due to an increased catalase activity.

Diet with isolated soy protein reduces oxidative stress and preserves ventricular function in rats with myocardial infarction

We investigated the effects of an isolated soy protein (ISP) diet offered over a 9-week period to rats in whom myocardial infarction (MI) had been induced, and a casein diet given as a control. Male Wistar rats were assigned to six groups after infarct size determination (n=8/group): Sham Casein (SC); Infarct Casein <25% (IC<25%); Infarct Casein >25% (IC>25%); Sham Soy (SS); Infarct Soy <25% (IS<25%); and Infarct Soy >25% (IS>25%). MI surgery was performed at the fifth week, and one month later, the animals were hemodynamically assessed to evaluate left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP), contractility and relaxation indexes (+/-dP/dt). Lung and liver specimens were also collected for the estimation of organ congestion. Oxidative stress was evaluated in heart homogenates through chemiluminescence (CL), carbonyl groups, and antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Infarcted groups treated with casein showed cardiac hypertrophy, lung and liver congestion, increased LVEDP and decreased LVSP and +/-dP/dt, all typical signals of heart failure. Ventricular dysfunction was correlated with increased myocardial oxidative damage as seen by CL and carbonyl groups data in the groups IC<25% and IC>25% (3 and 10-fold increase, respectively). The ISP diet was able to improve ventricular systolic and diastolic function in the groups IS<25% and IS>25% (LVEDP was reduced by 44% and 24%, respectively) and to decrease myocardial oxidative stress. The overall results confirm the preventive role of soy-derived products in terms of post-MI myocardial dysfunction probably by an antioxidant action.

Associação entre a qualidade de vida das mães e o estado nutricional de seus filhos

OBJETIVO: Verificar associacoes entre a qualidade de vida das maes e o estado nutricional de seus filhos. METODOS: Foi realizado um estudo caso-controle com maes de criancas com idade entre zero e cinco anos, moradoras da area de abrangencia de uma unidade basica de saude, no municipio de Porto Alegre. O calculo de tamanho amostral foi estimado em 152 maes, sendo 76 maes com filhos em risco nutricional/desnutricao (casos) e 76 maes com filhos eutroficos (controles). Foram coletadas informacoes referentes a qualidade de vida das maes, medida atraves do instrumento da Organizacao Mundial da Saude, e analisada a associacao entre a qualidade de vida materna e o estado nutricional de seus filhos. RESULTADOS: Em relacao ao dominio psiquico, para cada crianca eutrofica cuja mae tem baixa qualidade de vida existe uma chance de 5,4 criancas em risco nutricional/desnutricao com maes em igual condicao. No dominio ambiental, para cada crianca eutrofica cuja mae tem baixa qualidade de vida existe uma chance de 2,9 criancas em risco nutricional/desnutricao com maes em igual condicao. Em relacao ao nivel educacional, para cada crianca eutrofica cuja mae tem baixa qualidade de vida existe uma chance de 4,2 criancas em risco nutricional/desnutricao com maes em igual condicao. CONCLUSOES: A baixa qualidade de vida materna mostrou-se associada ao risco nutricional/desnutricao infantil e pode ser um fator de risco para o estado nutricional dos filhos.

Soft drink consumption reduces food intake in Wistar rats

Aims: To evaluate the effect of caloric and non-caloric soft drink intake on food consumption, body weight and composition, and metabolic parameters in rats. Methods: Controlled experimental study in which 30 male Wistar rats were divided into three groups and given food and beverage ad libitum during 17 weeks. The groups were as follows, according to the offered food: Control group – standard chow and water; Caloric soft drink group – standard chow, caloric soft drink, and water; and Non-caloric soft drink group – standard chow, non-caloric soft drink, and water. Results: There was no statistical difference in total energy intake, body weight, and fat deposition between groups. However, the chow energy intake was 45% lower in the caloric soft drink group compared to the control and non-caloric soft drink groups (198.7±0.7 kJ vs. 349.4±2.0 and 373.0±1.3 kJ, respectively), with 46% of the energy provided by the soft drink. The caloric soft drink group consumed 22% more carbohydrate, especially sucrose, compared to the control group (p<0.05). Macronutrient intake was not different between the control and non-caloric soft drink groups, but the caloric soft drink group consumed less protein and lipids when compared to the other groups (3.5±1.0 g of protein vs. 6.2±0.1 and 6.7±0.1 g, respectively; 0.7±0.01 g of lipids vs. 1.3±0.02 g and 1.4±0.02 g, respectively). Consumption of non-caloric soft drinks increased total sodium intake and consumption of both soft drinks decreased water intake. Although body weight varied during the experiment, there was no significant difference between groups at the end of the experiment, and no difference in fat deposition, fasting glucose, insulin and leptin, insulin resistance index, and lipid profile. Conclusions: The consumption of both types of soft drinks did not affect energy intake, body weight and composition, or metabolic parameters; however, it increased fluid intake and decreased water ingestion. Caloric soft drink intake influenced the amount and the quality of solid food consumed, compromising diet quality.