Effects of stress on catecholamine stores in central and peripheral tissues of long-term socially isolated rats

Both the peripheral sympatho-adrenomedullary and central catecholaminergic systems are activated by various psycho-social and physical stressors. Catecholamine stores in the hypothalamus, hippocampus, adrenal glands, and heart auricles of long-term socially isolated (21 days) and control 3-month-old male Wistar rats, as well as their response to immobilization of all 4 limbs and head fixed for 2 h and cold stress (4 degrees C, 2 h), were studied. A simultaneous single isotope radioenzymatic assay based on the conversion of catecholamines to the corresponding O-methylated derivatives by catechol-O-methyltransferase in the presence of S-adenosyl-1-(H-3-methyl)-methionine was used. The O-methylated derivatives were oxidized to H-3-vanilline and the radioactivity measured. Social isolation produced depletion of hypothalamic norepinephrine (about 18%) and hippocampal dopamine (about 20%) stores and no changes in peripheral tissues. Immobilization decreased catecholamine stores (approximately 39%) in central and peripheral tissues of control animals. However, in socially isolated rats, these reductions were observed only in the hippocampus and peripheral tissues. Cold did not affect hypothalamic catecholamine stores but reduced hippocampal. dopamine (about 20%) as well as norepinephrine stores in peripheral tissues both in control and socially isolated rats, while epinephrine levels were unchanged. Thus, immobilization was more efficient in reducing catecholamine stores in control and chronically isolated rats compared to cold stress. The differences in rearing conditions appear to influence the response of adult animals to additional stress. In addition, the influence of previous exposure to a stressor on catecholaminergic activity in the brainstem depends on both the particular catecholaminergic area studied and the properties of additional acute stress. Therefore, the sensitivity of the catecholaminergic system to habituation appears to be tissue-specific

Antioxidant Protection against Curative and Palliative Doses of Ionizing Irradiation in Human Blood Decreases with Aging

Reactive oxygen species (ROS) are independently recognized to play a significant role in radiation-induced damage on healthy tissue and in aging process. However, an age-related alteration of antioxidant (AO) system in radiation response in humans is poorly investigated. The aim of this paper was to evaluate the irradiation effects on the activities and expression of AO system in the blood of healthy women during aging. Blood samples were irradiated with curative and palliative doses of 2 Gy or 9 Gy γ-rays. AO capacity for detoxification of O2•− and H2O2 in response to 2 Gy γ-irradiation decreases in women above 58 years, while in response to 9 Gy shows signs of weakening after 45 years of age. Due to reduction of AO capacity during aging, cytotoxic effects of curative and palliative doses of irradiation, mediated by ROS, may significantly increase in older subjects, while removal of H2O2 excess could reduce them

Different behavioral effects of maprotiline and fluxilan in rats

Serotonin and noradrenaline are involved in the mechanisms of action of most antidepressant drugs. We examined the effects of chronic treatment with maprotiline, a selective inhibitor of noradrenaline reuptake, and fluxilan, a selective inhibitor of serotonin reuptake, on the behavior of unstressed controls and chronic unpredictable mild stress (CUMS) model rats in the forced swim test (FST) and elevated plus maze test. Both selective reuptake inhibitors resulted in a significant reduction of time spent in immobility. Climbing was significantly increased in maprotiline- and swimming was exclusively elicited in the fluxilan-treated unstressed control and CUMS rats. Maprotiline-treated animals displayed decreased anxiety and fluxilan-treated rats enhanced anxiety. The obtained results suggest that central noradrenergic and serotonergic systems might be affected differently during FST. The results also demonstrate that the anxiogenic effects of chronic fluxilan treatment are similar to those reported by many other studies. These differences observed for the effects of fluxilan in relation to those reported for maprotiline and probably due to the different pharmacological profiles of these drugs

Mutant p53 protein expression and antioxidant status deficiency in breast cancer

It is well recognized that cancers develop and grow as a result of disordered function of tumor suppressor genes and oncogenes, which may be exploited for screening purposes. Extensive evidence indicated tumor suppressor protein p53 as candidate marker for mutation identification. We have investigated mutant p53 protein expression in human breast tumors in relation to antioxidant status deficiency. The study included 100 breast cancer patients. p53 protein expression was evaluated by Western blot assay and immunostaining using a CM-1, DO-7 and Pab240 antibodies. Antioxidant parameters and lipid peroxidation were estimated by biochemical analyses. Western blotting with epitopespecific monoclonal antibody Pab240 strongly suggests that nuclear extracts from breast cancer cells express mutant forms of p53. It is of interest that the mutant forms of p53 overexpression in conjunction with the appearance of nuclear bodies are observed in highly aggressive carcinomas. Expression of isoform Δp53 (45 kDa) and isoform of ~ 29 kDa were more common in cases with LN metastasis. These studies point out the molecular consequences of oxidative stress (lipid peroxides, LP, p<0.001) and antioxidant status deficiency (copper, zinc superoxid dismutase, SOD, p<0.001; catalase, CAT, p<0.01; glutathione reductase, GR, p<0.001; glutathione, GSH, p<0.05) and indicate the importance of p53 mutation as the commonest genetic alteration detected in breast cancer cells. The expression of mutant p53 is correlated to increased lipid peroxides (0.346, p<0.05) and lowered antioxidant activity of CAT (- 0.437, p<0.01) in the breast cancer patients

Effects of acute stress on gene expression of splenic catecholamine biosynthetic enzymes in chronically stressed rats

The aim of this study was to examine how acute immobilization stress affects the concentrations of catecholamines in the plasma and the expression of the splenic catecholamine biosynthetic enzymes tyrosine hydroxylase (TH), dopamine-Я-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) in chronically socially isolated rats. We found that acute immobilization increases the plasma catecholamine levels and splenic PNMT protein levels in chronically socially isolated rats. These results show that acute stress of chronically stressed animals activates the sympatho-adrenomedullary system and increases synthesis of splenic PNMT by 37%, both of which can modulate the immune function. [Projekat Ministarstva nauke Republike Srbije, br. III 41027, br. III 41022 and br. ON 173044

Effects of chronic diazepam treatments on behavior on individually housed rats

The present study analyzed the effects of chronic treatment with low doses of diazepam on body weight, defecations and urinations, vertical rears, the elevated platform test; and self-grooming in male rats exposed for 21 days to social isolation. The rats were treated for 21 days with diazepam (0.2 mg/kg, i.p) or its vehicle. Social isolation led to decreased body weight and vertical rears, more defecations and urinations, increased reluctance to step down from the test platform, shorter duration of grooming, and longer reluctance to start grooming. Chronic diazepam in individually housed rats produced increase in body weight and vertical rears, decrease in the number of defecations and urinations, and shortening of the time of reluctance to step down from the platform. The number of grooming bouts, their duration, and reluctance to start grooming were not altered by diazepam, but it decreased the percentage of incorrect transitions. The obtained data indicate that chronic diazepam treatment of socially isolated rats changes non-grooming behavior and some grooming, behavior parameters

Changes of Hippocampal Noradrenergic Capacity in Stress Condition

This study aimed to investigate the effects of chronic restraint stress (CRS) on the protein levels of dopamine-β-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. © 2020 Charles University. All rights reserved

Animal Models for Chronic Stress-Induced Oxidative Stress in the Spleen: The Role of Exercise and Catecholaminergic System

We examined the effects of daily exercise on the gene expression of catecholamine biosynthetic enzymes (tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DBH), and phenyl ethanolamine N-methyltransferase (PNMT)), vesicular monoamine transporter 2 (VMAT 2), antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)), concentrations of catecholamines (noradrenaline (NA) and adrenaline (A)) and malondialdehyde (MDA), activities of monoamine oxidase (MAO), and antioxidant enzymes in the spleen of chronically psychosocially stressed rats. Exposure of chronically stressed rats to exercise increased the levels of PNMT protein by 19%, VMAT 2 mRNA by 100%, NA by 160%, and A by 140%; decreased/unchanged MAO enzyme activity; returned concentrations of MDA to control level; and increased CAT and GPx mRNA levels (50% and 150%, respectively). Exercise induced the accumulation of the catecholamines and a decrease of stress-induced oxidative stress in the spleen, which may significantly affect the immune-neuroendocrine interactions in stress conditions. Also, exercise induced the catecholaminergic system and antioxidant defense to become more ready to a novel stressor, which indicates that exercise may induce potentially positive physiological adaptations. Our combined model of chronic social isolation and long-term daily treadmill running in rats may be a good animal model in the research of therapeutic role of exercise in human disease caused by chronic stress

Antioxidant Status and Sex Hormones in Women with Simple Endometrial Hyperplasia

Cancer of the reproductive tract is an important source of morbidity and mortality among women worldwide. Factors affecting endometrial cancer and endometrial hyperplasia are known to be similar. Endometrial hyperplasia is abnormal proliferation of the glands and the stroma resulting in architectural and cytological modifications. Due to hormonal changes, this condition is most common among women who are nearing the menopause or have reached the menopause. Antioxidant system has a role in preventing cancer initiation and promotion. Since the carcinogenesis occurs in several stages, it is likely that the antioxidant defense depends on the type of cell and tissue. The objective of this study was to investigate whether antioxidant enzymes activities and lipid hydroperoxides concentration in patients with endometrial hyperplasia are influenced by the changes in sex hormones level (estradiol, progesterone, FSH, and LH) during the menstrual cycle and in postmenopause. The material we used consisted of blood and endometrial tissue specimens of women diagnosed with endometrial hyperplasia simplex. Patients were divided in groups depending on the phase of the menstrual cycle: follicular phase, luteal phase and postmenopause. The activities of antioxidant enzymes and the lipid hydroperoxides level were compared among the phases to test the differences and a linear regression model was used to evaluate the associations between hormone levels and antioxidant/oxidant variables. In the blood of examined patients, we observed a phase-related changes of LOOH concentrations. Significant negative correlation between FSH concentration and GR activity (r= -0.42, p<0.05) and significant positive correlation between LH and LOOH concentrations (r= 0.038, p<0.05) was found. In hyperplasia simplex tissue we recorded significant phase-related changes of LOOH level as well as of AO enzyme activities. SOD and CAT had similar activity pattern, which was higher in luteal phase and in postmenopause, compared to follicular phase (p<0.05). GPx and GR activities did not show any statistical difference. Also, negative correlation between progesterone and GR activity (r=-0.036, p<0.05) was observed. Hormonal influence on AO system is of importance in gynecological diseases etiology since they may promote cell proliferation but are also used in conservative therapy, especially for hyperplasia simplex. However, the role of ROS production as a risk factor for endometrial hyperplasia still needs to be clarified as well as the role of AO status in response to gonadotropins and sex steroids