RESUMEN
This study aimed to investigate the effects of chronic restraint stress (CRS) on the protein levels of dopamine-ß-hydroxylase (DBH), noradrenaline transporter (NET), vesicular monoamine transporter 2 (VMAT2) and brain-derived neurotrophic factor (BDNF), as well as the concentration of noradrenaline (NA) in the rat hippocampus. The investigated parameters were quantified by Western blot analyses and ELISA kits. We found that CRS increased the protein levels of DBH by 30 %, VMAT2 by 11 %, BDNF by 11 % and the concentration of NA by 104 %, but decreased the protein levels of NET by 16 % in the hippocampus of chronically stressed rats. The molecular mechanisms by which CRS increased the hippocampal NA level are an important adaptive phenomenon of the noradrenergic system in the stress condition.
Asunto(s)
Hipocampo/metabolismo , Norepinefrina/metabolismo , Estrés Psicológico/metabolismo , Animales , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Dopamina beta-Hidroxilasa/metabolismo , Proteínas de Transporte de Noradrenalina a través de la Membrana Plasmática/metabolismo , Ratas , Restricción Física , Proteínas de Transporte Vesicular de Monoaminas/metabolismoRESUMEN
Endometrial tissue is under a strong influence of sex hormones. These hormones are considered as developmental factors of endometrial hyperplasia and endometrial cancer. We examined the influence of gonadotropins (follicle-stimulating and luteinizing hormone) and sex hormones (estradiol, progesterone) on oxidant/antioxidant parameters in blood and endometrial tissue of women with complex endometrial hyperplasia. In blood, superoxide dismutase activity was significantly higher in luteal phase and postmenopause compared to the follicular phase. A significant phase-related difference of glutathione peroxidase and glutathione reductase activity was recorded in the endometrium. Both enzymes had lower activity in luteal phase and postmenopause compared to the follicular phase. The linear regression analysis of individual hormonal variables against antioxidant parameters showed negative correlation between glutathione peroxidase activity and gonadotropin concentrations in the endometrium. The regression of hyperplastic to normal endometrium is the purpose of conservative treatment based on administration of progestogens or gonadotropin-releasing hormone analogues. Our findings indicate that gonadotropins influence the antioxidant enzymes activity in women with complex endometrial hyperplasia, which may affect disease development. Further studies are needed to clarify the molecular basis of hormone action on antioxidant system that may potentially initiate a development of treatments based on redox-dependent mechanism.
Asunto(s)
Hiperplasia Endometrial/sangre , Hiperplasia Endometrial/patología , Estradiol/sangre , Hormona Folículo Estimulante/sangre , Hormona Luteinizante/sangre , Progesterona/sangre , Adulto , Antioxidantes/metabolismo , Hiperplasia Endometrial/metabolismo , Endometrio/metabolismo , Femenino , Fase Folicular , Glutatión Peroxidasa/metabolismo , Glutatión Reductasa/metabolismo , Humanos , Ensayo Inmunorradiométrico , Modelos Lineales , Fase Luteínica , Hormona Luteinizante/análisis , Posmenopausia , Radioinmunoensayo , Superóxido Dismutasa/sangreRESUMEN
Cancer of the reproductive tract is an important cause of morbidity and mortality among women worldwide. In this study we evaluated the influence of diagnostic categories, age and reproductive factors on antioxidant enzymes and lipid hydroperoxides in the blood of gynaecological patients diagnosed with endometrial polyp, myoma, hyperplasia simplex, hyperplasia complex and endometrial adenocarcinoma. Multivariate regression analysis was used to assess the association of diagnosis, age, parity, abortions and abnormal uterine bleeding with the examined parameters. Diagnosis provided the best predictive model for superoxide dismutase, catalase and glutathione peroxidase activities, and also for the lipid hydroperoxide level. Abortions fitted the best predictive model for superoxide dismutase activity. A significant correlation was also found between the predictor variables themselves. This study showed that reproductive and other factors may be associated, at least partially, with antioxidant capacity and ability to defend against the oxidative damage in gynaecological patients with various diagnoses.
Asunto(s)
Antioxidantes/metabolismo , Enfermedades de los Genitales Femeninos/sangre , Enfermedades de los Genitales Femeninos/diagnóstico , Reproducción , Adulto , Anciano , Catalasa/metabolismo , Femenino , Enfermedades de los Genitales Femeninos/enzimología , Humanos , Peróxidos Lipídicos , Persona de Mediana Edad , Análisis de Regresión , Superóxido DismutasaRESUMEN
The sympathoneural system has a profound influence on the heart function. Sympathetic neurons are the major contributors to the huge rise of circulating noradrenaline (NA) level in response to stressful stimuli. Treadmill training in rats is forced exercise which has the propensity to induce both psychological and physical stress. The aim of this study is to examine how chronic forced running (CFR) affects the expression of catecholamine biosynthetic enzymes (tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT)) and cAMP response element-binding (CREB) in stellate ganglia, as well as the concentrations of catecholamines, adrenocorticotropic hormone (ACTH) and corticosterone (CORT) in the plasma of rats. Also, we investigated how the additional acute immobilization stress changes the mentioned parameters. The rat training program consisted of 12 weeks running on a treadmill (20 m/min, 20 min/day). We found that CFR increases TH and DBH mRNA and protein levels in stellate ganglia, which is followed by increased NA concentration in the plasma. CFR reduces the level of PNMT mRNA, while the level of PNMT protein remains unchanged in stellate ganglia. The increased expression of TH and DBH genes positively correlates with the expression of CREB in stellate ganglia and with plasma ACTH level, while reduced level of PNMT mRNA in stellate ganglia correlates with reduced plasma CORT level. The additional acute immobilization stress increased gene expression of catecholamine biosynthetic enzymes in stellate ganglia, as well as catecholamines, ACTH and CORT levels in the plasma. The results presented here suggest that the continuous increase of the noradrenaline biosynthetic enzyme expression in stellate ganglia due to CFR may play a role in growing risk of cardiovascular diseases.
Asunto(s)
Enfermedades Cardiovasculares/enzimología , Catecolaminas/biosíntesis , Regulación Enzimológica de la Expresión Génica , Condicionamiento Físico Animal/efectos adversos , Ganglio Estrellado/metabolismo , Hormona Adrenocorticotrópica/sangre , Animales , Enfermedades Cardiovasculares/sangre , Enfermedades Cardiovasculares/etiología , Corticosterona/sangre , Masculino , Ratas , Ratas Wistar , Ganglio Estrellado/patologíaRESUMEN
Ovarian cancer still ranks first as the leading cause of death among gynecological malignancies. Malignant transformation of normal ovarian epithelial cells is caused by genetic alterations that disrupt regulation of proliferation, programmed cell death, and senescence. The vast majority of ovarian tumors arise due to accumulation of genetic damage, but the specific genetic pathways for the development of epithelial ovarian tumors, borderline and malignant, are largely unknown. Our results show that in progressive stages of carcinoma, the oxidative stress can contribute to the uncontrolled tumor expansion. Circulating levels of antioxidants may be important to consider when evaluating a woman's risk of cancer, even among women who are at higher predicted risk. The purpose of this article was to review the current approaches to molecular pathogenesis of borderline and invasive epithelial ovarian tumors.
Asunto(s)
Biomarcadores de Tumor/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Ováricas/genética , Biomarcadores de Tumor/metabolismo , Transformación Celular Neoplásica/genética , Femenino , Predisposición Genética a la Enfermedad , Humanos , Pérdida de Heterocigocidad , Invasividad Neoplásica , Neoplasias Ováricas/metabolismo , Neoplasias Ováricas/patología , Estrés Oxidativo/genética , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas p21(ras) , Factores de Riesgo , Transducción de Señal/genética , Proteína p53 Supresora de Tumor/genética , Proteínas ras/genéticaRESUMEN
Taking into consideration the biological importance of interaction between antioxidant defense (AD) enzymes and sexual steroid hormones it was deemed important to compare our recent achievements in the field with the state of current knowledge. The main goal of the present review was to investigate the changes of AD enzyme activities: superoxide dismutases, catalase, glutathione peroxidase, glutathione-S-transferase and glutathione reductase in the brain of female and male rats depending on progesterone and estradiol. These ovarian steroids produce their effects by acting on numerous target tissues and organs, such as the reproductive organs, bone tissue and cartilage, peripheral blood vessels and the central nervous system (CNS). We have chosen it as a new parameter that might represent an important indicator of the changes within the CNS, bearing in mind the biological importance of the enzymes of the AD system. Our experimental results indicate that the AD enzyme activities in the brain tissue of female and male rats show a certain dependence on the concentration of progesterone and estradiol. The present review suggests that the modulation of the oxidative and antioxidative capacity by sexual steroid hormones is mediated through antioxidant metabolizing enzymes.
Asunto(s)
Antioxidantes/metabolismo , Encéfalo/enzimología , Enzimas/metabolismo , Hormonas Esteroides Gonadales/metabolismo , Animales , Catalasa/metabolismo , Estradiol/metabolismo , Femenino , Glutatión Peroxidasa/metabolismo , Glutatión Reductasa/metabolismo , Glutatión Transferasa/metabolismo , Masculino , Progesterona/metabolismo , Ratas , Especies Reactivas de Oxígeno/metabolismo , Factores Sexuales , Superóxido Dismutasa/metabolismoRESUMEN
The review concerns a number of basic molecular pathways that play a crucial role in perception, transmission, and modulation of the stress signals, and mediate the adaptation of the vital processes in the cardiovascular system (CVS). These highly complex systems for intracellular transfer of information include stress hormones and their receptors, stress-activated phosphoprotein kinases, stress-activated heat shock proteins, and antioxidant enzymes maintaining oxidoreductive homeostasis of the CVS. Failure to compensate for the deleterious effects of stress may result in the development of different pathophysiological states of the CVS, such as ischemia, hypertension, atherosclerosis and infarction. Stress-induced dysbalance in each of the CVS molecular signaling systems and their contribution to the CVS malfunctioning is reviewed. The general picture of the molecular mechanisms of the stress-induced pathophysiology in the CVS pointed out the importance of stress duration and intensity as etiological factors, and suggested that future studies should be complemented by the careful insights into the individual factors of susceptibility to stress, prophylactic effects of 'healthy' life styles and beneficial action of antioxidant-rich nutrition.
Asunto(s)
Antioxidantes/metabolismo , Enfermedades Cardiovasculares/etiología , Sistema Cardiovascular/metabolismo , Sistemas Neurosecretores/metabolismo , Estrés Oxidativo , Estrés Fisiológico/complicaciones , Animales , Antioxidantes/uso terapéutico , Enfermedades Cardiovasculares/genética , Enfermedades Cardiovasculares/metabolismo , Enfermedades Cardiovasculares/prevención & control , Sistema Cardiovascular/enzimología , Dieta , Regulación de la Expresión Génica , Proteínas de Choque Térmico/metabolismo , Humanos , Estilo de Vida , Oxidación-Reducción , Fosforilación , Proteínas Quinasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Medición de Riesgo , Factores de Riesgo , Estrés Fisiológico/genética , Estrés Fisiológico/metabolismo , Estrés Fisiológico/terapiaRESUMEN
In order to examine if differences in activity and inducibility of antioxidative enzymes in rat cerebral cortex and hippocampus are underlying their different sensitivity to radiation, we exposed four-day-old female Wistar rats to cranial radiation of 3 Gy of gamma-rays. After isolation of hippocampus and cortex 1 h or 24 h following exposure, activities of copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT) were measured and compared to unirradiated controls. MnSOD protein levels were determined by SDS-PAGE electrophoresis and Western blot analysis. Our results showed that CuZnSOD activity in hippocampus and cortex was significantly decreased 1 h and 24 h after irradiation with 3 Gy of gamma-rays. MnSOD activity in both brain regions was also decreased 1 h after irradiation. 24 h following exposure, manganese SOD activity in hippocampus almost achieved control values, while in cortex it significantly exceeded the activity of the relevant controls. CAT activity in hippocampus and cortex remained stable 1 h, as well as 24 h after irradiation with 3 Gy of gamma-rays. MnSOD protein level in hippocampus and cortex decreased 1 h after irradiation with 3 Gy of gamma-rays. 24 h after exposure, MnSOD protein level in cortex was similar to control values, while in hippocampus it was still significantly decreased. We have concluded that regional differences in MnSOD radioinducibility are regulated at the level of protein synthesis, and that they represent one of the main reasons for region-specific radiosensitivity of the brain.
Asunto(s)
Antioxidantes/fisiología , Encéfalo/efectos de la radiación , Rayos gamma , Superóxido Dismutasa/efectos de la radiación , Animales , Antioxidantes/efectos de la radiación , Encéfalo/enzimología , Encéfalo/fisiología , Catalasa/efectos de la radiación , Corteza Cerebral/fisiología , Corteza Cerebral/efectos de la radiación , Femenino , Hipocampo/fisiología , Hipocampo/efectos de la radiación , Ratas , Ratas WistarRESUMEN
We studied the expression of pro-apoptotic neurotrophin receptor p75 (p75(NTR)) in human and murine retinoblastoma, compared to normal retina, and examined changes in p75(NTR) expression with the onset of apoptosis in the course of murine retinoblastoma progression, using immunohistochemistry and quantitative real-time RT-PCR. The murine retinoblastoma is induced by retinal specific expression of SV40 T-antigen (TAg), which blocks the function of the retinoblastoma protein (pRB) and related proteins, and is a well-studied model that closely simulates human retinoblastoma. The majority of human retinoblastoma either lacked or expressed decreased levels of p75(NTR) mRNA, compared to human retina. Moreover, p75(NTR) protein was not detected in any tumor studied, unlike normal retina. Like human retinoblastoma, advanced murine retinoblastoma did not express p75(NTR). However, before tumors emerged, small clusters of TAg-positive cells coexpressed p75(NTR) and activated caspase-3, a marker of apoptosis. Furthermore, in three rare human eyes containing retinoblastoma adjacent to regions resembling the benign retinal tumor retinoma, both normal retina and retinoma-like tissue expressed p75(NTR) protein, while the retinoblastoma did not. We suggest that p75(NTR) loss accompanies progression from retinoma to retinoblastoma.
Asunto(s)
Receptor de Factor de Crecimiento Nervioso/metabolismo , Neoplasias de la Retina/metabolismo , Retinoblastoma/metabolismo , Animales , Antígenos Transformadores de Poliomavirus/metabolismo , Apoptosis , Caspasa 3 , Caspasas/metabolismo , Progresión de la Enfermedad , Activación Enzimática , Humanos , Ratones , Ratones Endogámicos C57BL , Receptor de Factor de Crecimiento Nervioso/genética , Retina/citología , Retina/metabolismo , Neoplasias de la Retina/genética , Neoplasias de la Retina/patología , Retinoblastoma/genética , Retinoblastoma/patología , Proteína de Retinoblastoma/genética , Proteína de Retinoblastoma/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Tumorales CultivadasRESUMEN
The study deals with activity of three antioxidant enzymes, copper, zinc-superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD), catalase (CAT) in hippocampus of rats, following the exposure to single chronic (individual housing or forced swimming) and acute (immobilization or cold) stress, as well as to combined chronic/acute stress. In addition, plasma noradrenaline (NA) and adrenaline (A) concentrations were measured in the same stress conditions, because their autooxidation can add to the oxidative stress. We observed that i) long-term social isolation and repeated forced swimming had minor effects on plasma catecholamines, but in the long-term pretreated groups, acute stressors caused profound elevation NA and A levels, ii) chronic stressors activate antioxidant enzymes, iii) acute stressors decrease catalase activity, their effects on CuZnSOD appear to be stressor-dependent, whereas MnSOD is not affected by acute stressors, and iv) pre-exposure to chronic stress affects the antioxidant-related effects of acute stressors, but this effect depends to a large extent on the type of the chronic stressor. Based on both metabolic and neuroendocrine data, long-term isolation appears to be a robust psychological stressor and to induce a "priming" effect specifically on the CuZnSOD and CAT activity.
Asunto(s)
Médula Suprarrenal/fisiología , Catalasa/metabolismo , Hipocampo/enzimología , Estrés Fisiológico/metabolismo , Superóxido Dismutasa/metabolismo , Sistema Nervioso Simpático/fisiología , Animales , Antioxidantes/metabolismo , Frío , Epinefrina/sangre , Masculino , Norepinefrina/sangre , Estrés Oxidativo/fisiología , Ratas , Ratas Wistar , Restricción Física , Estrés Fisiológico/fisiopatología , NataciónRESUMEN
The sensitivity of copper,zinc (CuZn)- and manganese (Mn)-superoxide dismutase (SOD) to exogenous estradiol benzoate (EB) was investigated in Wistar rats during postnatal brain development. Enzyme activities were measured in samples prepared from brains of rats of both sexes and various ages between 0 and 75 days, treated sc with 0.5 æg EB/100 g body weight in 0.1 ml olive oil/100 g body weight, 48 and 24 h before sacrifice. In females, EB treatment stimulated MnSOD activity on days 0 (66.1 percent), 8 (72.7 percent) and 15 (81.7 percent). In males, the stimulatory effect of EB on MnSOD activity on day 0 (113.6 percent) disappeared on day 8 and on days 15 and 45 it became inhibitory (40.3 and 30.5 percent, respectively). EB had no effect on the other age groups. The stimulatory effect of EB on CuZnSOD activity in newborn females (51.8 percent) changed to an inhibitory effect on day 8 (38.4 percent) and disappeared by day 45 when inhibition was detected again (48.7 percent). In males, the inhibitory effect on this enzyme was observed on days 0 (45.0 percent) and 15 (28.9 percent), and then disappeared until day 60 when a stimulatory effect was observed (38.4 percent). EB treatment had no effect on the other age groups. The sensitivity of MnSOD to estradiol differed significantly between sexes during the neonatal and prepubertal period, whereas it followed a similar pattern thereafter. The sensitivity of CuZnSOD to estradiol differed significantly between sexes during most of the study period. Regression analysis showed that the sensitivity of MnSOD to this estrogen tended to decrease similarly in both sexes, whereas the sensitivity of CuZnSOD showed a significantly different opposite tendency in female and male rats. These are the first reports indicating hormonal modulation of antioxidant enzyme activities related to the developmental process
Asunto(s)
Animales , Masculino , Femenino , Ratas , Antioxidantes , Encéfalo , Superóxido Dismutasa , Encéfalo , Ratas Wistar , Superóxido DismutasaRESUMEN
The brain is widely responsive to gonadal hormones. The functional significance of ovarian hormones in the brain is evident from biochemical studies indicating that estradiol or progesterone treatment of testectomized rats produces changes of antioxidant enzyme activities. The effect of estradiol benzoate (EB) and progesterone (P) in the control of antioxidant (AO) enzyme activities was studied in the brain of adult male Wistar rats. The activities of catalase (CAT), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST) and glutathione reductase (GR) were measured in appropriate subcellular fractions, prepared from brains of animals belonging to various experimental groups. These groups were designed with the intention to follow changes in enzyme activities 2 h or 24 h after systemic administration of 5 microg EB or 2 mg P to testectomized (TX) animals. The obtained results show that both EB and P increase CAT activity, whereas EB decreases GSH-Px, GST and GR activities. These findings clearly show the modulatory role of EB and P in the control of enzymes responsible for the protection of rat nerve cells against oxidative damage caused by free oxygen radicals.
Asunto(s)
Antioxidantes/metabolismo , Encéfalo/efectos de los fármacos , Encéfalo/enzimología , Estradiol/análogos & derivados , Estradiol/farmacología , Oxidorreductasas/biosíntesis , Progesterona/farmacología , Animales , Catalasa/biosíntesis , Activación Enzimática/efectos de los fármacos , Glutatión Peroxidasa/biosíntesis , Glutatión Reductasa/biosíntesis , Glutatión Transferasa/biosíntesis , Hormonas Esteroides Gonadales/farmacología , Masculino , Ratas , Ratas Endogámicas WFRESUMEN
The sensitivity of copper,zinc (CuZn)- and manganese (Mn)-superoxide dismutase (SOD) to exogenous estradiol benzoate (EB) was investigated in Wistar rats during postnatal brain development. Enzyme activities were measured in samples prepared from brains of rats of both sexes and various ages between 0 and 75 days, treated sc with 0.5 micro g EB/100 g body weight in 0.1 ml olive oil/100 g body weight, 48 and 24 h before sacrifice. In females, EB treatment stimulated MnSOD activity on days 0 (66.1%), 8 (72.7%) and 15 (81.7%). In males, the stimulatory effect of EB on MnSOD activity on day 0 (113.6%) disappeared on day 8 and on days 15 and 45 it became inhibitory (40.3 and 30.5%, respectively). EB had no effect on the other age groups. The stimulatory effect of EB on CuZnSOD activity in newborn females (51.8%) changed to an inhibitory effect on day 8 (38.4%) and disappeared by day 45 when inhibition was detected again (48.7%). In males, the inhibitory effect on this enzyme was observed on days 0 (45.0%) and 15 (28.9%), and then disappeared until day 60 when a stimulatory effect was observed (38.4%). EB treatment had no effect on the other age groups. The sensitivity of MnSOD to estradiol differed significantly between sexes during the neonatal and prepubertal period, whereas it followed a similar pattern thereafter. The sensitivity of CuZnSOD to estradiol differed significantly between sexes during most of the study period. Regression analysis showed that the sensitivity of MnSOD to this estrogen tended to decrease similarly in both sexes, whereas the sensitivity of CuZnSOD showed a significantly different opposite tendency in female and male rats. These are the first reports indicating hormonal modulation of antioxidant enzyme activities related to the developmental process.
Asunto(s)
Antioxidantes/farmacología , Encéfalo/enzimología , Estradiol/análogos & derivados , Estradiol/farmacología , Superóxido Dismutasa/efectos de los fármacos , Animales , Encéfalo/efectos de los fármacos , Encéfalo/crecimiento & desarrollo , Femenino , Masculino , Ratas , Ratas Wistar , Superóxido Dismutasa/metabolismoRESUMEN
The activity of mitochondrial superoxide dismutase (MnSOD) and cytosol superoxide dismutase (CuZnSOD) was measured in corresponding subcellular fractions prepared from the thymi of intact and chronically gonadectomized (GX) rats of both sexes, as well as of GX male and female rats injected subcutaneously with a single dose of 5 microg estradiol benzoate (EB) and/or 2 mg progesterone (P). Animals were sacrificed 2 h or 24 h following hormone treatment. In the females, the activity of MnSOD in the thymus was stable during the estrous cycle and did not change after ovariectomy. Treatment of GX females with estradiol benzoate resulted 2 h later in a significant elevation of MnSOD activity, whereas 24 h later the activity returned back to control values. On the other hand, treatment of GX females with progesterone had no effect on the MnSOD activity. However, combined hormone treatment, in which EB injection preceded progesterone injection by one hour, enhanced the effect on MnSOD activity similar to that of estradiol benzoate alone. The activity of CuZnSOD in cycling rats was increased in proestrus, whereas removal of the ovaries kept the values at low diestrus and estrus levels. Contrary to MnSOD, CuZnSOD activity did not change after EB treatment of GX females, while progesterone increased the enzyme activity at 2 h and 24 h after hormone treatment. However, combined EB+P treatment proved to be ineffective. In the males, neither MnSOD nor CuZnSOD activity was affected by the removal of testes or by progesterone treatment of GX animals. Only EB injection to GX rats significantly increased CuZnSOD activity 24 h later.
Asunto(s)
Estradiol/farmacología , Progesterona/farmacología , Superóxido Dismutasa/metabolismo , Timo/enzimología , Animales , Citosol/enzimología , Diestro , Estradiol/análogos & derivados , Estro , Femenino , Masculino , Mitocondrias/enzimología , Orquiectomía , Ovariectomía , Proestro , Ratas , Ratas Wistar , Timo/ultraestructuraRESUMEN
The goal of this study was to provide data on the dose-dependent production of dicentrics and micronuclei in human lymphocytes irradiated with 22.6 MeV protons and to estimate the possible contribution of intracellular superoxide dismutases (SOD) to the relative biological effectiveness (RBE) of protons. For the dose-response study, heparinized whole blood of a healthy volunteer was irradiated with protons and X-rays employing radiation doses of 0.5-4 Gy. Three biological endpoints were analyzed: chromosomal aberrations, micronuclei, and specific activity of cytosolic (CuZnSOD) and mitochondrial (MnSOD) superoxide dismutases in harvested human blood cells. Dicentric dose-response curves fit a linear-quadratic form (alpha = 0.094 +/- 0.006, beta = 0.032 +/- 0.001) induced with X-rays and (alpha = 0.119 +/- 0.057, beta = 0.029 +/- 0.014) for 22.6 MeV protons. Protons were more effective than X-rays in producing exchanges, particularly at 0.5 and 1 Gy. In contrast to X-ray irradiated samples where a significant increase in the specific activity of MnSOD was recorded (up to a radiation dose of 1 Gy), irradiation with protons markedly reduced its activity. As a consequence of the reduced activity of MnSOD, the chromosomal dose-response curve became quadratic. The RBE for dicentrics varies with dose (from 2.2 to 1.01) and reduced activity of MnSOD is an important contributor to the RBE of protons. SODs, particularly MnSOD, play an important role in defending DNA from reactive oxygen species. A reduced activity of SOD, particularly MnSOD, is an important contributor to the RBE of protons.
Asunto(s)
Aberraciones Cromosómicas , Linfocitos/enzimología , Linfocitos/efectos de la radiación , Micronúcleos con Defecto Cromosómico/efectos de la radiación , Superóxido Dismutasa/metabolismo , División Celular/efectos de la radiación , Relación Dosis-Respuesta en la Radiación , Humanos , Técnicas In Vitro , Linfocitos/ultraestructura , Pruebas de Micronúcleos , ProtonesRESUMEN
The marked variability in radiation response among individuals of the same age group prompted us to investigate the role of antioxidative enzyme activity. Micronuclei (MN) and enzyme assays were performed on blood samples of healthy male volunteers. The procedure consisted of micronucleus analysis and measurement of the superoxide dismutase (SOD) activity in harvested blood samples irradiated in vitro with 2 Gy gamma-rays and in unirradiated control samples for each individual. We found that the yield of radiation-induced micronuclei was in the range of 112 to 378 micronuclei per 1000 binucleated cells. The activity of cytosol superoxide dismutase (CuZnSOD) was reduced, whereas the activity of manganese superoxide dismutase (MnSOD) was markedly elevated in the blood samples harvested in lymphocyte cultures after irradiation. The analysis of our results showed that MnSOD plays the most important role in radiation-induced cellular damage. The results of this investigation showed that measurement of micronuclei and the activities of SOD in harvested human blood cells can serve as a rapid predictive assay of radiosensitivity in a clinical setting.
Asunto(s)
Antioxidantes/farmacología , Superóxido Dismutasa/metabolismo , Adulto , Daño del ADN/efectos de la radiación , Humanos , Linfocitos/efectos de la radiación , Masculino , Pruebas de Micronúcleos , Traumatismos por Radiación/enzimología , Tolerancia a RadiaciónRESUMEN
The activities of glutathione dependent antioxidant enzymes were measured in subcellular fractions of whole brain homogenates prepared from ovariectomized (OVX) female rats, untreated or treated 2 h or 24 h prior to sacrifice with a single dose of 2 mg progesterone (P) or 5 micrograms estradiol benzoate (EB). Glutathione peroxidase (GSH-Px) activity was not changed following systemic administration of EB, but P increased GSH-Px in the brain of OVX rats 24 h after the treatment. The activity of glutathione reductase (GR) was suppressed by EB short time, only 2 h following treatment, whereas P increased the enzyme activity 24 h after treatment. On the other hand, the activities of catalase (CAT) and glutathione-S-transferase (GST) were not changed following systemic administration of EB or P. The present work was carried out to study the involvement of ovarian steroids, especially P, in the control of GSH-Px and GR activities, and our results suggest that oxidative stress in the brain of female rats may be modulated by the level of progesterone.
Asunto(s)
Antioxidantes/metabolismo , Encéfalo/efectos de los fármacos , Encéfalo/enzimología , Estradiol/análogos & derivados , Glutatión/metabolismo , Progesterona/farmacología , Animales , Catalasa/metabolismo , Estradiol/farmacología , Femenino , Glutatión Peroxidasa/metabolismo , Glutatión Reductasa/metabolismo , Glutatión Transferasa/metabolismo , Ovario/fisiología , Ratas , Factores de TiempoRESUMEN
Changes in the activity of brain antioxidant superoxide dismutases (SOD) were followed in newborn and young female rats 8, 15, 30, 45, 60 and 75 days after birth treated with olive oil. In newborn rats, the content of brain cytosol SOD (CuZnSOD) and mitochondrial SOD (MnSOD) decreased after treatment with olive oil. However, in the brain of rats aged 8 days this effect was lost. The suppressive effect of olive oil on these enzymes reappeared again in 15-day-old rats. In rats aged one month, only the activity of CuZnSOD was reduced after olive oil treatment. In the brain of rats aged 45, 60 and 75 days, neither MnSOD nor CuZnSOD were affected by olive oil. The different effects of olive oil on the brain SOD, during ontogeny suggest that profound changes in the susceptibility of nervous tissue antioxidant enzymes to olive oil take place during sexual maturation.
Asunto(s)
Animales Recién Nacidos/metabolismo , Encéfalo/enzimología , Aceites de Plantas/farmacología , Superóxido Dismutasa/metabolismo , Animales , Encéfalo/ultraestructura , Citosol/enzimología , Femenino , Mitocondrias/enzimología , Aceite de Oliva , Aceites de Plantas/administración & dosificación , Ratas , Ratas WistarRESUMEN
Enzymatic activities of glutathione peroxidase, glutathione-S-transferase, glutathione reductase and catalase, as well as the glutathione content were measured in the brain tissue of regularly cycling rats at dioestrus, proestrus and estrus. The activity of glutathione peroxidase was found to be suppressed at proestrus, whereas that of catalase was increased at dioestrus. Glutathione transferase and glutathione reductase activities, as well as the glutathione content appeared to be stable during the oestrous cycle. These results suggest that, in the female rat, glutathione peroxidase and catalase activities in the brain tissue are influenced by the ovarian hormone status.
Asunto(s)
Encéfalo/metabolismo , Estro/metabolismo , Glutatión/metabolismo , Glutatión/fisiología , Oxidorreductasas/metabolismo , Animales , Catalasa/metabolismo , Diestro/metabolismo , Femenino , Glutatión Peroxidasa/metabolismo , Proestro/metabolismo , Ratas , Ratas WistarRESUMEN
The transcription factor E2F and its regulation by pRB and related pocket proteins are central to cell cycle control in higher eukaryotes. Much of our knowledge of this regulation has come from studies using immediate-early proteins of DNA tumor viruses. Previously, we reported that the 72-kDa immediate-early region 1 gene product of the human cytomegalovirus, IE72, transactivates the dihydrofolate reductase promoter through the E2F site and that it physically interacts with E2F1 (M. J. Margolis, S. Pajovic, E. L. Wong, M. Wade, R. Jupp, J. A. Nelson, and J. C. Azizkhan, J. Virol. 69:7759-7767, 1995). In this study, we further characterized the mechanism by which IE72 modulates E2F-dependent transcription. In vitro phosphorylation reactions using gel-purified bacterially expressed proteins revealed that IE72 is a kinase that autophosphorylates and phosphorylates E2F1, -2, and -3 (but not E2F4 or -5) and the RB-related pocket proteins p130 and p107 (but not pRB). The region of IE72 spanning amino acids 173 to 197 shows a high level of homology to the ATP binding sites in over 500 kinases. The kinase-negative protein IE72deltaATP, from which this region has been deleted, cannot activate E2F-dependent transcription. The kinase activity of IE72 is also required for its ability to reduce the association of E2F4 with p107 and p130. Taken together, these data suggest that the kinase activity of IE72 is required for E2F-dependent transcriptional activation and that this is likely to result from phosphorylation of specific members of the E2F and pocket protein families by IE72.