The aim was to determine whether the dietary glycemic index (GI) related to coronary heart disease (CHD) risk and whether oxidized LDL could explain this relation. Nine prospective cohorts of GI or glycemic load (GL) associations were pooled in a meta-analysis and showed an increased risk of CHD for high GI (near significant at RR=1.13, 95%CI; 1.00-1.26) and GL diets (significant at RR=1.40, 95%CI; 1.17-1.68), both with significant evidence of heterogeneity (P<0.07). Sera from 151 type 2 diabetics who completed a 6-month trial of a low GI diet demonstrated no treatment difference in measures of oxidative damage. However, when data from both treatments were pooled, oxidized LDL as a marker of CHD risk inversely related to low GI carbohydrate intake. We conclude that GI and GL relate to CHD and oxidative damage to LDL may explain part of this association.

Traumatic brain injury (TBI) is a prominent disease in developed countries, and age is an important factor in functional outcome. Although aged patients typically show diminished recovery compared to young patients, and have higher mortality and morbidity following TBI, the mechanism is not well understood. To date, there is no effective therapeutic for TBI. Previous studies indicate a secondary injury in TBI begins immediately after impact, and is likely the major contribution to delayed neuron dysfunction and loss. Studies also suggest mitochondrial dysfunction and increased free radical species (ROS) production following TBI may play a key role in the process. To evaluate oxidative damage following TBI, especially in aging, young (3 months), middle aged (12 months) and aged (22 months) Fisher-344 rats were subjected to a unilateral controlled cortical impact (CCI) injury, and tissue sparing, 4-hydroxynonenal (HNE) and acrolein levels, and antioxidant enzyme activities, and DNA oxidative damage were measured. In order to evaluate changes in mitochondria following TBI, mitochondrial protein levels were investigated using young adult animals. To evaluate a potential therapeutic for TBI, the effect of creatine on oxidative damage was evaluated. These studies show an age dependent increase of oxidative damage following TBI, demonstrated by increased levels of 4-HNE, acrolein and 8-hydroxyguanine. Middle aged and aged animals showed increased tissue loss compared to young animals 7 days post injury. Mitochondrial proteins involved in the respiratory chain, carrier proteins and channel proteins were significantly decreased 24 h post injury in ipsilateral cortex, but increased in both ipsilateral and contralateral hippocampus. To study potentially protective compounds in TBI, animals were fed with creatine two weeks before TBI and showed less oxidative damage and increased antioxidant capacity, which suggests creatine may be a potential drug for clinical treatment of TBI. The work described in this dissertation is the first to show increased oxidative damage and diminished antioxidant capacity in TBI in aging. The study of mitochondriafollowing TBI using quantitative proteomics is also the first time to show multiple mitochondrial proteins change following TBI. These data are also the first to show creatine can increase antioxidant defenses. These studies contribute to our understanding the mechanisms of secondary injury in TBI in aging.

A reprodução é capaz de alterar muitos parâmetros relacionados à fisiologia, ao comportamento e à morfologia em vertebrados machos. Trabalhos apresentam relação entre reprodução ou envelhecimento com estresse oxidativo, não havendo trabalho relacionando estresse oxidativo, reprodução e envelhecimento simultaneamente em mamíferos. Para avaliar o estresse oxidativo no encéfalo de ratos machos decorrente da atividade reprodutiva e ao longo do envelhecimento (3, 6, 12 e 24 meses) comparado a animais sem atividade reprodutiva (n = 10 por grupo e por idade), avaliou-se a atividade de enzimas antioxidantes (catalase, glutationa peroxidase, superóxido dismutase, glutationa Stransferase); os níveis de moléculas antioxidantes (glutationa oxidada e reduzida, vitamina C e E); os marcadores de dano oxidativo (peroxidação lipídica, carbonilação de proteínas, nitritos e nitratos), bem como o status oxidante total e a atividade da enzima metabólica aconitase no encéfalo, e os níveis de testosterona e estradiol no soro. ANOVA, seguido do post hoc de Tukey, foi utilizado para avaliar a diferença estatística entre os grupos. Correlação de Spearman e Regressão Linear (método stepwise) foram utilizadas para avaliar alterações relacionadas entre os parâmetros. Os animais machos com atividade reprodutiva apresentaram elevada concentração de testosterona e atividade da aconitase, sugerindo um metabolismo mais elevado que os sem atividade reprodutiva. A atividade das enzimas antioxidantes e a quantidade de moléculas antioxidantes também foram mais elevadas em diversos grupos de animais reprodutores, mas o dano oxidativo mais elevado também foi observado nesses grupos de animais reprodutores. Alterações relacionadas ao envelhecimento foram observadas em ambos os grupos, não havendo padrão. Observou-se elevada atividade das enzimas antioxidantes, bem como maiores danos, no grupo dos animais reprodutores de 6 meses. Nos animais mais velhos (24 meses), observam-se similares níveis dos marcadores de dano oxidativo, atividade de algumas enzimas antioxidantes e de moléculas antioxidantes entre os grupos. Do complexo emaranhado de correlações e regressões observado nesse sistema, destaca-se a influência do envelhecimento nos níveis de testosterona, nitritos e nitratos e na atividade das enzimas aconitase, catalase e glutationa Stransferase (coeficiente padronizado B = 0,53; 0,31; 0,39; 0,78 e 0,23, respectivamente). Os níveis de testosterona se correlacionaram positivamente com diversos parâmetros: catalase 73%, superóxido dismutase 71%, peroxidação lipídica 43%, nitritos e nitratos 50%, aconitase 46% e aconitase reativada 47%. Sugere-se que a atividade reprodutiva eleva o metabolismo, tanto por estímulo hormonal quanto por outras alterações, e.g. alteração comportamental, levando a elevada produção de espécies reativas, causando dano oxidativo e elevando a atividade e a quantidade das defesas antioxidantes. Esses resultados auxiliam na compreensão das alterações causadas pela reprodução relacionadas ao envelhecimento em nível de estresse oxidativo, e sugere bases para explicar os custos relacionados à reprodução. / Reproduction causes changes in male vertebrates, including morphological, behavioral, and physiological alterations. Reproduction and aging may alter oxidative stress, but there is no research concerning oxidative stress and reproduction during aging in mammals. We performed a comprehensive study to examine oxidative stress in the brains of male rats with (experienced) or without (naïve) reproductive activity during aging (3, 6, 12, and 24 months of age). Oxidative stress was assessed by measuring the antioxidant enzymes activity (catalase, glutathione peroxidase, superoxide dismutase, glutathione S-transferase), the amount of non-enzymatic compounds (reduced and oxidized glutathione, vitamin C and E), the levels of oxidative damage markers (lipid peroxidation, protein carbonylation, nitrite and nitrate) as well as total oxidant status, and the aconitase metabolic enzyme activity in brain, and the levels of testosterone and estradiol in serum. ANOVA, followed by Tukey post hoc, was used to analyze statistical differences among groups. Spearman Correlation and Linear Regression (stepwise method) were used to analyze relation among parameters. Reproductively active animals exhibited increased testosterone levels and aconitase activity, suggesting an increased metabolism. Despite the Increased antioxidant enzyme activities and increased levels of antioxidant compounds were observed, damage to biomolecules was also observed in experienced rats. During aging changes in oxidative stress were observed in all groups, but no pattern was observed. We found higher activities of antioxidant enzymes, higher amounts of antioxidants, contrasting with higher damage at six months of age between experienced than naïve animals. Some similarities were found in antioxidant activities and levels, and damage between the groups at twenty-four months of age. Correlations and regressions show a very complex web of interactions among the parameters. Aging exerted influence in testosterone, nitrites and nitrates levels, in the aconitase, catalase, and glutathione Stransferase activities (adjusted B value of = -0.53; -0.31; - 0.39; -0.78; and 0.23, respectively). Testosterone levels positively correlated with: catalase 73%, superoxide dismutase 71%, lipid peroxidation 43%, nitrites and nitrates 50%, aconitase 46%, and reactivated aconitase 47%. We suggest that reproductive activity increases metabolism, by hormonal stimuli as by others factors, e.g. behavioral change, and this changes lead to increased production of reactive species, which lead to oxidative damage and increases the antioxidant enzymes activity and non-enzymatic amount. These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.

Base teórica: As doenças hepáticas representam um grande problema de saúde pública, sendo responsáveis por um considerável número de atendimentos e internações hospitalares, com crescente índice de mortalidade. A melatonina (MLT), uma potente molécula antioxidante, tem-se mostrado benéfica em diversas situações patológicas, incluindo as hepáticas. Objetivo: O objetivo foi avaliar os efeitos da MLT na cirrose hepática induzida por CCl4 em ratos machos Wistar. Métodos: Utilizaram-se 20 ratos machos Wistar, (230-250g), divididos em 4 grupos: I: Controle (CO), II: CO+MLT, III: CCl4 e IV: CCl4+MLT. O CCl4 foi administrado i.p.: 10 aplicações de 5 em 5 dias, 10 aplicações de 4 em 4 dias, e 7 aplicações de 3 em 3 dias. A MLT (20mg/Kg i.p.) iniciada na 10ª semana, perdurando até o final do experimento na 16ª semana. Resultados: Como resultados apresentados nos dois artigos, observamos que a MLT no grupo CCl4+MLT, em relação ao grupo CCl4, diminuiu os níveis séricos das enzimas AST, ALT e FA. Na avaliação do estresse oxidativo, diminuiu a LPO avaliada por TBARS e F2-isoprostanos; aumentou a atividade da enzima antioxidante (SOD) e diminuiu a expressão da NQO1; aumentou a expressão do fator de transcrição Nrf2 e diminuiu a expressão de seu inibidor o Keap1. Na avaliação do estresse do RE, diminuiu a expressão de proteínas preditoras de estresse do RE, GRP78 e ATF6. Na avaliação das proteínas e fatores de choque térmico, diminuiu a expressão da HSP70 e do HSF1. No processo inflamatório, diminuiu a presença de infiltrado inflamatório e a expressão das proteínas NF-KB/p65 e da iNOS. No processo fibrogênico, diminuiu os septos e a presença de nódulos de fibrose, além de diminuir a expressão das proteínas TGF-β1 e da α-SMA. No processo de angiogênese, diminuiu a expressão do VEGF. Conclusão: Com este estudo, demonstramos que a MLT, uma indolamina sintetizada a partir do aminoácido triptofano, protegeu o parênquima hepático da progressão da fibrose induzida em ratos pelo CCl4. / Background: Conclusion Liver diseases represent a major problem in public health, accounting for a significant number of hospitalizations and care, with increasing mortality rates. Melatonin (MLT) is a powerful antioxidant molecule, that has demonstrated to be beneficial in various pathological situations, including liver diseases. Objective: The aim was to evaluate the effects of MLT in liver cirrhosis induced by CCl4 in male Wistar rats. Methods: We used 20 male Wistar rats (230- 250g) divided into 4 groups: I : control (CO), II: CO + MLT, III: CCl4 and IV: CCl4 + MLT. The CCl4 was administered ip: 10 applications in 5 to 5 days , 10 applications in 4 to 4 days and 7 applications in 3 to 3 days. The MLT (20 mg / kg ip) started at the 10th week and lasted until the end of the experiment, at 16 weeks. Results: As results presented in the two articles, we found that the MLT in the CCl4+MLT group when compared to CCl4 group, decreased serum levels of AST, ALT and FA enzymes. In the evaluation of oxidative stress, decreased LPO measured by TBARS and F2- isoprostanes; increased the activity of the antioxidant enzyme (SOD) and decreased the expression of NQO1; increased expression of the transcription factor Nrf2 and decreased the expression of its inhibitor Keap1. In the assessment of ER stress, decreased the expression of proteins predictors of ER stress, GRP78 and ATF6. In the evaluation of proteins and heat shock factors, decreased expression of HSP70 and HSF1. In the inflammatory process, decreased inflammatory infiltration and the expression of proteins NF-KB/p65 and iNOS. In the fibrogenic process, decreased the sept and the presence of nodules of fibrosis, in addition to decreasing the expression of TGF-β1 protein and α-SMA. In the process of angiogenesis, decreased expression of VEGF. Conclusion: In this study, we demonstrated that MLT, an indoleamine synthesized from tryptophan, protected the liver parenchyma from fibrosis progression induced by CCl4 in rats.

A reprodução é capaz de alterar muitos parâmetros relacionados à fisiologia, ao comportamento e à morfologia em vertebrados machos. Trabalhos apresentam relação entre reprodução ou envelhecimento com estresse oxidativo, não havendo trabalho relacionando estresse oxidativo, reprodução e envelhecimento simultaneamente em mamíferos. Para avaliar o estresse oxidativo no encéfalo de ratos machos decorrente da atividade reprodutiva e ao longo do envelhecimento (3, 6, 12 e 24 meses) comparado a animais sem atividade reprodutiva (n = 10 por grupo e por idade), avaliou-se a atividade de enzimas antioxidantes (catalase, glutationa peroxidase, superóxido dismutase, glutationa Stransferase); os níveis de moléculas antioxidantes (glutationa oxidada e reduzida, vitamina C e E); os marcadores de dano oxidativo (peroxidação lipídica, carbonilação de proteínas, nitritos e nitratos), bem como o status oxidante total e a atividade da enzima metabólica aconitase no encéfalo, e os níveis de testosterona e estradiol no soro. ANOVA, seguido do post hoc de Tukey, foi utilizado para avaliar a diferença estatística entre os grupos. Correlação de Spearman e Regressão Linear (método stepwise) foram utilizadas para avaliar alterações relacionadas entre os parâmetros. Os animais machos com atividade reprodutiva apresentaram elevada concentração de testosterona e atividade da aconitase, sugerindo um metabolismo mais elevado que os sem atividade reprodutiva. A atividade das enzimas antioxidantes e a quantidade de moléculas antioxidantes também foram mais elevadas em diversos grupos de animais reprodutores, mas o dano oxidativo mais elevado também foi observado nesses grupos de animais reprodutores. Alterações relacionadas ao envelhecimento foram observadas em ambos os grupos, não havendo padrão. Observou-se elevada atividade das enzimas antioxidantes, bem como maiores danos, no grupo dos animais reprodutores de 6 meses. Nos animais mais velhos (24 meses), observam-se similares níveis dos marcadores de dano oxidativo, atividade de algumas enzimas antioxidantes e de moléculas antioxidantes entre os grupos. Do complexo emaranhado de correlações e regressões observado nesse sistema, destaca-se a influência do envelhecimento nos níveis de testosterona, nitritos e nitratos e na atividade das enzimas aconitase, catalase e glutationa Stransferase (coeficiente padronizado B = 0,53; 0,31; 0,39; 0,78 e 0,23, respectivamente). Os níveis de testosterona se correlacionaram positivamente com diversos parâmetros: catalase 73%, superóxido dismutase 71%, peroxidação lipídica 43%, nitritos e nitratos 50%, aconitase 46% e aconitase reativada 47%. Sugere-se que a atividade reprodutiva eleva o metabolismo, tanto por estímulo hormonal quanto por outras alterações, e.g. alteração comportamental, levando a elevada produção de espécies reativas, causando dano oxidativo e elevando a atividade e a quantidade das defesas antioxidantes. Esses resultados auxiliam na compreensão das alterações causadas pela reprodução relacionadas ao envelhecimento em nível de estresse oxidativo, e sugere bases para explicar os custos relacionados à reprodução. / Reproduction causes changes in male vertebrates, including morphological, behavioral, and physiological alterations. Reproduction and aging may alter oxidative stress, but there is no research concerning oxidative stress and reproduction during aging in mammals. We performed a comprehensive study to examine oxidative stress in the brains of male rats with (experienced) or without (naïve) reproductive activity during aging (3, 6, 12, and 24 months of age). Oxidative stress was assessed by measuring the antioxidant enzymes activity (catalase, glutathione peroxidase, superoxide dismutase, glutathione S-transferase), the amount of non-enzymatic compounds (reduced and oxidized glutathione, vitamin C and E), the levels of oxidative damage markers (lipid peroxidation, protein carbonylation, nitrite and nitrate) as well as total oxidant status, and the aconitase metabolic enzyme activity in brain, and the levels of testosterone and estradiol in serum. ANOVA, followed by Tukey post hoc, was used to analyze statistical differences among groups. Spearman Correlation and Linear Regression (stepwise method) were used to analyze relation among parameters. Reproductively active animals exhibited increased testosterone levels and aconitase activity, suggesting an increased metabolism. Despite the Increased antioxidant enzyme activities and increased levels of antioxidant compounds were observed, damage to biomolecules was also observed in experienced rats. During aging changes in oxidative stress were observed in all groups, but no pattern was observed. We found higher activities of antioxidant enzymes, higher amounts of antioxidants, contrasting with higher damage at six months of age between experienced than naïve animals. Some similarities were found in antioxidant activities and levels, and damage between the groups at twenty-four months of age. Correlations and regressions show a very complex web of interactions among the parameters. Aging exerted influence in testosterone, nitrites and nitrates levels, in the aconitase, catalase, and glutathione Stransferase activities (adjusted B value of = -0.53; -0.31; - 0.39; -0.78; and 0.23, respectively). Testosterone levels positively correlated with: catalase 73%, superoxide dismutase 71%, lipid peroxidation 43%, nitrites and nitrates 50%, aconitase 46%, and reactivated aconitase 47%. We suggest that reproductive activity increases metabolism, by hormonal stimuli as by others factors, e.g. behavioral change, and this changes lead to increased production of reactive species, which lead to oxidative damage and increases the antioxidant enzymes activity and non-enzymatic amount. These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.

Base teórica: As doenças hepáticas representam um grande problema de saúde pública, sendo responsáveis por um considerável número de atendimentos e internações hospitalares, com crescente índice de mortalidade. A melatonina (MLT), uma potente molécula antioxidante, tem-se mostrado benéfica em diversas situações patológicas, incluindo as hepáticas. Objetivo: O objetivo foi avaliar os efeitos da MLT na cirrose hepática induzida por CCl4 em ratos machos Wistar. Métodos: Utilizaram-se 20 ratos machos Wistar, (230-250g), divididos em 4 grupos: I: Controle (CO), II: CO+MLT, III: CCl4 e IV: CCl4+MLT. O CCl4 foi administrado i.p.: 10 aplicações de 5 em 5 dias, 10 aplicações de 4 em 4 dias, e 7 aplicações de 3 em 3 dias. A MLT (20mg/Kg i.p.) iniciada na 10ª semana, perdurando até o final do experimento na 16ª semana. Resultados: Como resultados apresentados nos dois artigos, observamos que a MLT no grupo CCl4+MLT, em relação ao grupo CCl4, diminuiu os níveis séricos das enzimas AST, ALT e FA. Na avaliação do estresse oxidativo, diminuiu a LPO avaliada por TBARS e F2-isoprostanos; aumentou a atividade da enzima antioxidante (SOD) e diminuiu a expressão da NQO1; aumentou a expressão do fator de transcrição Nrf2 e diminuiu a expressão de seu inibidor o Keap1. Na avaliação do estresse do RE, diminuiu a expressão de proteínas preditoras de estresse do RE, GRP78 e ATF6. Na avaliação das proteínas e fatores de choque térmico, diminuiu a expressão da HSP70 e do HSF1. No processo inflamatório, diminuiu a presença de infiltrado inflamatório e a expressão das proteínas NF-KB/p65 e da iNOS. No processo fibrogênico, diminuiu os septos e a presença de nódulos de fibrose, além de diminuir a expressão das proteínas TGF-β1 e da α-SMA. No processo de angiogênese, diminuiu a expressão do VEGF. Conclusão: Com este estudo, demonstramos que a MLT, uma indolamina sintetizada a partir do aminoácido triptofano, protegeu o parênquima hepático da progressão da fibrose induzida em ratos pelo CCl4. / Background: Conclusion Liver diseases represent a major problem in public health, accounting for a significant number of hospitalizations and care, with increasing mortality rates. Melatonin (MLT) is a powerful antioxidant molecule, that has demonstrated to be beneficial in various pathological situations, including liver diseases. Objective: The aim was to evaluate the effects of MLT in liver cirrhosis induced by CCl4 in male Wistar rats. Methods: We used 20 male Wistar rats (230- 250g) divided into 4 groups: I : control (CO), II: CO + MLT, III: CCl4 and IV: CCl4 + MLT. The CCl4 was administered ip: 10 applications in 5 to 5 days , 10 applications in 4 to 4 days and 7 applications in 3 to 3 days. The MLT (20 mg / kg ip) started at the 10th week and lasted until the end of the experiment, at 16 weeks. Results: As results presented in the two articles, we found that the MLT in the CCl4+MLT group when compared to CCl4 group, decreased serum levels of AST, ALT and FA enzymes. In the evaluation of oxidative stress, decreased LPO measured by TBARS and F2- isoprostanes; increased the activity of the antioxidant enzyme (SOD) and decreased the expression of NQO1; increased expression of the transcription factor Nrf2 and decreased the expression of its inhibitor Keap1. In the assessment of ER stress, decreased the expression of proteins predictors of ER stress, GRP78 and ATF6. In the evaluation of proteins and heat shock factors, decreased expression of HSP70 and HSF1. In the inflammatory process, decreased inflammatory infiltration and the expression of proteins NF-KB/p65 and iNOS. In the fibrogenic process, decreased the sept and the presence of nodules of fibrosis, in addition to decreasing the expression of TGF-β1 protein and α-SMA. In the process of angiogenesis, decreased expression of VEGF. Conclusion: In this study, we demonstrated that MLT, an indoleamine synthesized from tryptophan, protected the liver parenchyma from fibrosis progression induced by CCl4 in rats.

A reprodução é capaz de alterar muitos parâmetros relacionados à fisiologia, ao comportamento e à morfologia em vertebrados machos. Trabalhos apresentam relação entre reprodução ou envelhecimento com estresse oxidativo, não havendo trabalho relacionando estresse oxidativo, reprodução e envelhecimento simultaneamente em mamíferos. Para avaliar o estresse oxidativo no encéfalo de ratos machos decorrente da atividade reprodutiva e ao longo do envelhecimento (3, 6, 12 e 24 meses) comparado a animais sem atividade reprodutiva (n = 10 por grupo e por idade), avaliou-se a atividade de enzimas antioxidantes (catalase, glutationa peroxidase, superóxido dismutase, glutationa Stransferase); os níveis de moléculas antioxidantes (glutationa oxidada e reduzida, vitamina C e E); os marcadores de dano oxidativo (peroxidação lipídica, carbonilação de proteínas, nitritos e nitratos), bem como o status oxidante total e a atividade da enzima metabólica aconitase no encéfalo, e os níveis de testosterona e estradiol no soro. ANOVA, seguido do post hoc de Tukey, foi utilizado para avaliar a diferença estatística entre os grupos. Correlação de Spearman e Regressão Linear (método stepwise) foram utilizadas para avaliar alterações relacionadas entre os parâmetros. Os animais machos com atividade reprodutiva apresentaram elevada concentração de testosterona e atividade da aconitase, sugerindo um metabolismo mais elevado que os sem atividade reprodutiva. A atividade das enzimas antioxidantes e a quantidade de moléculas antioxidantes também foram mais elevadas em diversos grupos de animais reprodutores, mas o dano oxidativo mais elevado também foi observado nesses grupos de animais reprodutores. Alterações relacionadas ao envelhecimento foram observadas em ambos os grupos, não havendo padrão. Observou-se elevada atividade das enzimas antioxidantes, bem como maiores danos, no grupo dos animais reprodutores de 6 meses. Nos animais mais velhos (24 meses), observam-se similares níveis dos marcadores de dano oxidativo, atividade de algumas enzimas antioxidantes e de moléculas antioxidantes entre os grupos. Do complexo emaranhado de correlações e regressões observado nesse sistema, destaca-se a influência do envelhecimento nos níveis de testosterona, nitritos e nitratos e na atividade das enzimas aconitase, catalase e glutationa Stransferase (coeficiente padronizado B = 0,53; 0,31; 0,39; 0,78 e 0,23, respectivamente). Os níveis de testosterona se correlacionaram positivamente com diversos parâmetros: catalase 73%, superóxido dismutase 71%, peroxidação lipídica 43%, nitritos e nitratos 50%, aconitase 46% e aconitase reativada 47%. Sugere-se que a atividade reprodutiva eleva o metabolismo, tanto por estímulo hormonal quanto por outras alterações, e.g. alteração comportamental, levando a elevada produção de espécies reativas, causando dano oxidativo e elevando a atividade e a quantidade das defesas antioxidantes. Esses resultados auxiliam na compreensão das alterações causadas pela reprodução relacionadas ao envelhecimento em nível de estresse oxidativo, e sugere bases para explicar os custos relacionados à reprodução. / Reproduction causes changes in male vertebrates, including morphological, behavioral, and physiological alterations. Reproduction and aging may alter oxidative stress, but there is no research concerning oxidative stress and reproduction during aging in mammals. We performed a comprehensive study to examine oxidative stress in the brains of male rats with (experienced) or without (naïve) reproductive activity during aging (3, 6, 12, and 24 months of age). Oxidative stress was assessed by measuring the antioxidant enzymes activity (catalase, glutathione peroxidase, superoxide dismutase, glutathione S-transferase), the amount of non-enzymatic compounds (reduced and oxidized glutathione, vitamin C and E), the levels of oxidative damage markers (lipid peroxidation, protein carbonylation, nitrite and nitrate) as well as total oxidant status, and the aconitase metabolic enzyme activity in brain, and the levels of testosterone and estradiol in serum. ANOVA, followed by Tukey post hoc, was used to analyze statistical differences among groups. Spearman Correlation and Linear Regression (stepwise method) were used to analyze relation among parameters. Reproductively active animals exhibited increased testosterone levels and aconitase activity, suggesting an increased metabolism. Despite the Increased antioxidant enzyme activities and increased levels of antioxidant compounds were observed, damage to biomolecules was also observed in experienced rats. During aging changes in oxidative stress were observed in all groups, but no pattern was observed. We found higher activities of antioxidant enzymes, higher amounts of antioxidants, contrasting with higher damage at six months of age between experienced than naïve animals. Some similarities were found in antioxidant activities and levels, and damage between the groups at twenty-four months of age. Correlations and regressions show a very complex web of interactions among the parameters. Aging exerted influence in testosterone, nitrites and nitrates levels, in the aconitase, catalase, and glutathione Stransferase activities (adjusted B value of = -0.53; -0.31; - 0.39; -0.78; and 0.23, respectively). Testosterone levels positively correlated with: catalase 73%, superoxide dismutase 71%, lipid peroxidation 43%, nitrites and nitrates 50%, aconitase 46%, and reactivated aconitase 47%. We suggest that reproductive activity increases metabolism, by hormonal stimuli as by others factors, e.g. behavioral change, and this changes lead to increased production of reactive species, which lead to oxidative damage and increases the antioxidant enzymes activity and non-enzymatic amount. These results add comprehensive data regarding changes in oxidative stress during aging, and suggest an explanation for the costs of reproduction.

Base teórica: As doenças hepáticas representam um grande problema de saúde pública, sendo responsáveis por um considerável número de atendimentos e internações hospitalares, com crescente índice de mortalidade. A melatonina (MLT), uma potente molécula antioxidante, tem-se mostrado benéfica em diversas situações patológicas, incluindo as hepáticas. Objetivo: O objetivo foi avaliar os efeitos da MLT na cirrose hepática induzida por CCl4 em ratos machos Wistar. Métodos: Utilizaram-se 20 ratos machos Wistar, (230-250g), divididos em 4 grupos: I: Controle (CO), II: CO+MLT, III: CCl4 e IV: CCl4+MLT. O CCl4 foi administrado i.p.: 10 aplicações de 5 em 5 dias, 10 aplicações de 4 em 4 dias, e 7 aplicações de 3 em 3 dias. A MLT (20mg/Kg i.p.) iniciada na 10ª semana, perdurando até o final do experimento na 16ª semana. Resultados: Como resultados apresentados nos dois artigos, observamos que a MLT no grupo CCl4+MLT, em relação ao grupo CCl4, diminuiu os níveis séricos das enzimas AST, ALT e FA. Na avaliação do estresse oxidativo, diminuiu a LPO avaliada por TBARS e F2-isoprostanos; aumentou a atividade da enzima antioxidante (SOD) e diminuiu a expressão da NQO1; aumentou a expressão do fator de transcrição Nrf2 e diminuiu a expressão de seu inibidor o Keap1. Na avaliação do estresse do RE, diminuiu a expressão de proteínas preditoras de estresse do RE, GRP78 e ATF6. Na avaliação das proteínas e fatores de choque térmico, diminuiu a expressão da HSP70 e do HSF1. No processo inflamatório, diminuiu a presença de infiltrado inflamatório e a expressão das proteínas NF-KB/p65 e da iNOS. No processo fibrogênico, diminuiu os septos e a presença de nódulos de fibrose, além de diminuir a expressão das proteínas TGF-β1 e da α-SMA. No processo de angiogênese, diminuiu a expressão do VEGF. Conclusão: Com este estudo, demonstramos que a MLT, uma indolamina sintetizada a partir do aminoácido triptofano, protegeu o parênquima hepático da progressão da fibrose induzida em ratos pelo CCl4. / Background: Conclusion Liver diseases represent a major problem in public health, accounting for a significant number of hospitalizations and care, with increasing mortality rates. Melatonin (MLT) is a powerful antioxidant molecule, that has demonstrated to be beneficial in various pathological situations, including liver diseases. Objective: The aim was to evaluate the effects of MLT in liver cirrhosis induced by CCl4 in male Wistar rats. Methods: We used 20 male Wistar rats (230- 250g) divided into 4 groups: I : control (CO), II: CO + MLT, III: CCl4 and IV: CCl4 + MLT. The CCl4 was administered ip: 10 applications in 5 to 5 days , 10 applications in 4 to 4 days and 7 applications in 3 to 3 days. The MLT (20 mg / kg ip) started at the 10th week and lasted until the end of the experiment, at 16 weeks. Results: As results presented in the two articles, we found that the MLT in the CCl4+MLT group when compared to CCl4 group, decreased serum levels of AST, ALT and FA enzymes. In the evaluation of oxidative stress, decreased LPO measured by TBARS and F2- isoprostanes; increased the activity of the antioxidant enzyme (SOD) and decreased the expression of NQO1; increased expression of the transcription factor Nrf2 and decreased the expression of its inhibitor Keap1. In the assessment of ER stress, decreased the expression of proteins predictors of ER stress, GRP78 and ATF6. In the evaluation of proteins and heat shock factors, decreased expression of HSP70 and HSF1. In the inflammatory process, decreased inflammatory infiltration and the expression of proteins NF-KB/p65 and iNOS. In the fibrogenic process, decreased the sept and the presence of nodules of fibrosis, in addition to decreasing the expression of TGF-β1 protein and α-SMA. In the process of angiogenesis, decreased expression of VEGF. Conclusion: In this study, we demonstrated that MLT, an indoleamine synthesized from tryptophan, protected the liver parenchyma from fibrosis progression induced by CCl4 in rats.

The primary objective of this proposal was to determine whether mitochondrial oxidative stress and variation in a particular mtDNA lineage contribute to the risk of developing cortical dysplasia and are potential contributing factors in epileptogenesis in children. The occurrence of epilepsy in children is highly associated with malformations of cortical development (MCD). It appears that MCD might arise from developmental errors due to environmental exposures in combination with inherited variation in response to environmental exposures and mitochondrial function. Therefore, it is postulated that variation in a particular mtDNA lineage of children contributes to the effects of mitochondrial DNA damage on MCD phenotype. Quantitative PCR and dot blot were used to examine mitochondrial oxidative damage and single nucleotide polymorphism (SNP) in the mitochondrial genome in brain tissue from 48 pediatric intractable epilepsy patients from Miami Children’s Hospital and 11 control samples from NICHD Brain and Tissue Bank for Developmental Disorders. Epilepsy patients showed higher mtDNA copy number compared to normal health subjects (controls). Oxidative mtDNA damage was lower in non-neoplastic but higher in neoplastic epilepsy patients compared to controls. There was a trend of lower mtDNA oxidative damage in the non-neoplastic (MCD) patients compared to controls, yet, the reverse was observed in neoplastic (MCD and Non-MCD) epilepsy patients. The presence of mtDNA SNP and haplogroups did not show any statistically significant relationships with epilepsy phenotypes. However, SNPs G9804A and G9952A were found in higher frequencies in epilepsy samples. Logistic regression analysis showed no relationship between mtDNA oxidative stress, mtDNA copy number, mitochondrial haplogroups and SNP variations with epilepsy in pediatric patients. The levels of mtDNA copy number and oxidative mtDNA damage and the SNPs G9952A and T10010C predicted neoplastic epilepsy, however, this was not significant due to a small sample size of pediatric subjects. Findings of this study indicate that an increase in mtDNA content may be compensatory mechanisms for defective mitochondria in intractable epilepsy and brain tumor. Further validation of these findings related to mitochondrial genotypes and mitochondrial dysfunction in pediatric epilepsy and MCD may lay the ground for the development of new therapies and prevention strategies during embryogenesis.

The nucleotide excision repair pathway (NER) has been shown to efficiently remove bulky base lesions from the DNA, including those induced by solar light. It has been suggested that the NER pathway may be involved also in removing smaller oxidative base lesions from the DNA. Oxidative damage in the cell is caused by cellular aerobic respiration, with base damage to the nucleotides of the DNA being the most biologically relevant. One of the most common oxidative base lesions in the genome is the 7 ,8-dihydro-8-oxoguanine (8-oxoG). This lesion is pre-mutagenic since it can base pair with equal efficiency to the correct cytosine base, or the incorrect adenine base during DNA replication. Oxidative damage, including 8-oxoG, is repaired primarily by the base excision repair (BER) pathway, which is a multi-step, multi-protein pathway similar to NER. One key protein involved in both BER and NER is the p53 protein, which can act as a transcription factor and protein regulator to influence DNA repair. We have used a recombinant non-replicating human adenovirus, Ad5HCMVlacZ, which expresses the ~-galactosidase (~-gal) reporter gene, to examine the role of several NER proteins and the p53 protein in the BER of oxidative damage in human cells. Methylene blue (MB) acts as a photosenstizer, and after irradiation by visible light (VL) produces reactive oxygen species that cause 8-0xoG in the DNA. By infecting several normal, NER deficient and p53 deficient -tumor, primary and transformed fibroblast cell lines with a MB+VL-treated Ad5HCMVlacZ reporter construct, we were able to determine the host cell reactivation (HCR) of the oxidatively damaged reporter. Results indicate that the HCR of the MB+VL-treated reporter and the expression of p53 are enhanced by UVC pretreatment in normal human fibroblasts, suggesting that p53 may be involved in inducible BER. In addition, increased expression of p53 facilitated by pre-infection of normal cells with p53 expressing Ad5p53wt similarly enhanced HCR in the normal fibroblasts, giving further evidence that increased expression of p53 alone enhances BER. In contrast, although UVC pretreatment of p53 compromised cells resulted in enhanced HCR, the enhanced HCR did not correlate with enhanced p53 expression, suggesting that enhancement in BER can result from both p53 dependent and p53 independent mechanisms. We report also that HCR of the MB+VL-treated reporter gene was substantially reduced in SV40-transformed XP-C cells, with little or no reduction in SV40-transformed XPA, XPD, XPF, XPG and CSB cells, suggesting a role for the XPC protein in the BER ofMB+VL-induced DNA damage. In particular, the XPC protein appears to be involved in both the constitutive and inducible aspects of BER, as the HCR of the MB + VL-treated reporter was reduced in 3 UVC pretreated as well as untreated XP-C primary human fibroblast strains. In addition, pre-infection of cells with Ad5p53wt, resulted in an enhanced HCR of normal but not XP-C deficient fibroblasts consistent with a p53 dependent involvement of the XPC protein in BER of MB+VL-treated DNA. Additional studies were also conducted to determine the cell sensitivity of normal and NER deficient SV40-transformed cell lines to MB and MB+VL. The results show that MB alone and MC+VL are toxic to cells, and that cells deficient in NER are not more sensitive to MC or MB+VL compared to NER proficient normal cells. In fact, the NER deficient cell lines were more resistant to MB alone compared to NER proficient normal cells. In particular, although the SV40- transformed XP-C cell line showed a significant reduction in HCR of the MB-Vl-treated reporter gene, suggesting a deficiency in the repair of MB+VL-induced DNA damage, the SV40-transformed XP-C cells were not more sensitive to MB or MB+VL. This suggests that the toxicity of human cells to MB and MB+VL results primarily from damage to cellular components other than DNA such as membrane structures including the mitochondria and lysozomes as has been reported for other photosensitizers. / Thesis / Master of Science (MSc)