Response of liver antioxidant defense system to acute and chronic physical and psychological stresses in male rats

The aim of this study was to evaluate the effect of acute and chronic physical and psychological stressors on the induction of oxidative stress in male rat liver. Male Wistar rats were randomly divided into 3 groups as following: control, physical and psychological stress groups. Stress was induced by communication box for one (acute), fifteen and thirty (chronic) days. Once stressor periods ended, rats were anesthetized and their liver dissected out for later assessments. Exposure to physical stress enhanced liver superoxide dismutase (SOD) (19.44 %) and glutathione S-transferase (GST) (21.84 %) activities and decreased glutathione (GSH) (30.03 %) level on the 1st day (p<0.05). SOD (24.13 and 18.43 %) and GST (27.77 and 21.27 %) activities were significantly increased, while catalase activity (29.74 and 24.41 %) and GSH level (35.05 and 31.05 %) were decreased in psychological stress group after 1 and 15 days (p<0.01 and p<0.05) compared to the 1st day value in control group, respectively. Psychological stress induced an increase in liver malondialdehyde (MDA) (46 %) and plasma corticosterone (36 %) levels on the 1st day (p<0.05). However, all parameters returned to their basal value after 30 days of stress. The results suggest that exposure to acute physical and psychological stressors induce the production of reactive oxygen species and oxidative stress in rat liver due to GSH depletion and the decreased catalase activity. The elevation of lipid peroxidation and corticosterone level in acute psychological stress may lead to more profound oxidative damage than acute physical stress. Moreover, cell protection in hepatic tissue of chronically stressed rats is indicative of possible late adaptation of the animals to stress

Polyhydroxylated fullerene nanoparticles attenuate brain infarction and oxidative stress in rat model of ischemic stroke

Oxidative stress is the common underlying mechanism of damage in ischemic stroke. Therefore, we aimed to evaluate the possible protective effects of polyhydroxylated fullerene derivatives on brain infarction and oxidative/nitrosative stress in a rat model of ischemic stroke. The experiment was performed by four groups of rats (each; n=12); Sham, Control ischemia, and ischemic treatment groups (Pretreatment and Posttreatment). Brain ischemia was induced by 90 min middle cerebral artery occlusion (MCAO) followed by 24 hours reperfusion. Rats received fullerene nanoparticles at dose of 1 mg/kg 30 min before MCAO and immediately after beginning of reperfusion. Infarct volume, contents of malondialdehyde (MDA), glutathione (GSH) and nitrate as well as superoxide dismutase (SOD) activity were assessed 24 hours after termination of MCAO. Brain infarct volume was 310 ± 21 mm3 in control group. Administration of fullerene nanoparticles before and after MCAO significantly decreased the infarct volume by 53 % (145 ± 45 mm3) and 81 % (59 ± 13 mm3), respectively. Ischemia also enhanced MDA and nitrate contents of ischemic hemispheres by 45 % and 25 % , respectively. Fullerene nanoparticles considerably reduced the MDA and nitrate contents of ischemic hemispheres before MCAO by 58 % and 17 % , respectively, and after MCAO by 38 % and 21 % , respectively. Induction of MCAO significantly decreased GSH content (19 % ) and SOD activity (52 % ) of ischemic hemispheres, whereas fullerene nanoparticles increased the GSH content and SOD activity of ischemic hemispheres by 19 % and 52 % before MCAO, respectively, and 21 % and 55 % after MCAO, respectively. Our findings indicate that fullerene nanoparticles, as a potent scavenger of free radicals, protect the brain cells against ischemia/reperfusion injury and inhibit brain oxidative/nitrosative damage

The Role of Fas-FasL Signaling Pathway in Induction of Apoptosis in Patients with Sulfur Mustard-Induced Chronic Bronchiolitis

Sulfur mustard (SM) is an alkylating agent that induces apoptosis and necrosis in cells. Fas-Fas ligand (FasL) interaction could induce apoptosis as well. In this study, it was hypothesized that apoptosis might play an important role in the pathogenesis of SM-induced lung injury via Fas-FasL signaling pathway. In a case-control study, Fas and FasL levels, caspase-3 activity and percent of apoptotic cells were measured in bronchoalveolar lavage (BAL) fluid of patients 20 years after exposure to sulfur mustard and compared with the control group. Results show that Fas and FasL levels were significantly higher in BAL fluid cells in patients group compared with the control (P = .001). No significant differences were observed between mild and moderate-severe groups. BAL fluid cells caspase-3 activity was not significantly different among the mild, moderate-severe, and control groups. The data suggest that Fas-FasL-induced apoptosis was impaired in BAL fluid cells of SM-exposed patients which might be one of the initiators of pathogenesis in SM-induced lung injury in these patients

Ameliorative effect of sixteen weeks endurance training on biochemical and oxidative damage in high fat diet induced obese rats

Obesity is mainly caused by consumption of high fat diet (HFD) and a lack of physical activity. Physical activity is an efficient strategy to delay development of obesity. In this studyv we tried to evaluate attenuating properties of 16 weeks endurance training on plasma oxidative stress and some biochemical parameters in HFD induced obese rats. Twenty-four male Wistar rats were randomly divided into four groups: standard diet group (SD), standard diet with endurance training group (ESD), HFD group and HFD with endurance training group (EHFD). After sixteen weeks, plasma was prepared and evaluated for measurement of different parameters. The results showed that HFD significantly decreased the activities of superoxide dismutase (33.58%), catalase (26.51%) and glutathione S-transferase (22.77%), while endurance training increased these enzymes activities. However, exercise ameliorated the increased malondialdehyde level and depletion of glutathione. In addition, it significantly reduced the increased levels of liver enzymes activities and lipid profiles. These findings suggest that endurance training has found to have beneficial effects against HFD-induced oxidative damage through increasing reduced antioxidants levels and inhibition of lipid peroxidation due to its antioxidant property. Thus, it can be considered an interesting strategy for the management of obesity related diseases

Organelle Isolation for Proteomics: Mitochondria from Peripheral Blood Mononuclear Cells

Mitochondria play key roles in many cell functions including energy production, fatty acid metabolism, pyrimidine biosynthesis, calcium homeostasis, and aging. They also regulate crucial signaling cascades such as apoptosis and oxidative stress. The proteome is often used to investigate the functional correlations on protein levels. Based upon the human, genome there is estimated 2000 to 2500 associated mitochondrial proteins, however, just over 600-800 have been identified at the protein level. For this reason, mitochondria contain a great number of proteins that have yet to be identified and characterized. The identification of these proteins can help in discovery of biological process. This protocol focuses on step-by-step procedure of mitochondrial proteome extraction from peripheral blood mononuclear cell (PBMC) mitochondria. The isolation and preparation procedures described here require 6 hours approximately

Protective effect of crocin against reperfusion-induced cardiac arrhythmias in anaesthetized rats

The aim of the present study was to investigate the effects of crocin - a natural antioxidant derived from saffron - on cardiac reperfusion-induced arrhythmia and antioxidant systems such as catalase and superoxide dismutase (SOD) enzyme activities, glutathione (GSH) and malondialdehyde (MDA, as a marker of lipid peroxidation) levels. Rats in 4 experimental groups were administered crocin (20 mg/kg/day) or vehicle (i.p.) for 21 days with or without cardiac ischemia-reperfusion (IR). At the end of this period, hearts of anaesthetized animals in IR and “Cr + IR” groups were subjected to 10 min occlusion of the left anterior descending coronary artery and thereafter reperfused for 30 min. The results suggest that crocin is partially capable of suppressing reperfusion-induced arrhythmias. Compared to control group, ischemic-reperfusion injury significantly decreased SOD activity and GSH level and increased MDA level of heart muscle. “Cr + IR” group showed remarkably increased catalase activity in heart tissue (28.7 ± 6.6 vs. 23.6 ± 4.1 U/mg protein, P < 0.05) compared to the IR group. The level of cardiac tissue SOD activity in the “Cr + IR” group animals did not decline significantly compared to rats that were administered crocin alone with no ischemia. The results suggest a protective role of crocin on cardiac reperfusion arrhythmias which may at least partially be related to stability or even amplification of antioxidant systems. Crocin may potentially be useful for treatment or prevention of arrhythmias in patients with ischemic heart disease and this issue remains to be investigated in future clinical studies

Comparison of Lecture and Blended Teaching Methods on Learning and Satisfaction of Medical Students in Biochemistry Course

Introduction: Considering the importance of biochemistry for medical students, its teaching methods are important. Using the appropriate teaching methods, teachers are trying to improve the effective learning and knowledge retention of students. The aim of this study was to determine the effects of lecture and blended teaching methods on learning of medical students in biochemistry course and also to assess students’ satisfaction from the blended method. Methods: In this quasi-experimental study, 60 medical students of Baqiyatallah (a.s) University of Medical Sciences who had selected biochemistry in the academic year 2011-2012 were randomly divided into two groups as experiment and control. To assess their knowledge, students were given a pre-test. Then, the control group received instruction through lecture method and the experiment group formed 5-member subgroups and received instruction through a blend of lecture and group discussion method. Then, both groups took a post-test. Also, the attitude of experimental group was assessed by a researcher-made Likert scale questionnaire. The data were analyzed through INSTAT software using t-test. Results: There was no statistically significant difference between the mean of pre-test and post-test scores in the two groups. Students in the experiment group, believed the method leads to a better feeling (63%) and satisfaction (96%) about biochemistry course, internal motivation to learn biochemistry (43%), and a better student and teacher relationship (96%). Conclusion: Blended teaching method could be useful in teaching biochemistry of medical students by promoting learner's internal motivation, increasing learning and satisfaction

Induction of Oxidative Stress in Skin and Lung of Infected BALB/C Mice with Iranian Strain of Leishmania major (MRHO/IR/75/ER)

  Background: The aim of this study was to investigate the effects of Leishmania major infection on the induction of oxidative stress in skin and lung of female mice. Methods: BALB/c mice were randomly divided into the control and experi-mental groups. The experimental groups were subcutaneously infected with in-oculums promastigotes of L. major. The animals were sacrificed at 20, 40, 60, 90 and 120 days post-infection, and tissues were isolated and analyzed. Results: Superoxide dismutase activity, percent of DNA fragmentation and su-peroxide anion production levels were increased in skin and lung of infected mice. Lung catalase activity and skin malondialdehyde level were also increased. The decreased glutathione level was observed in both tissues. The highest altera-tion in these parameters in both tissues was observed at 90 days post-infection. Conclusion: L. major infection induces the production of free radicals and oxida-tive stress in a time-dependent manner in mice skin and lung by depletion of glu-tathione and increasing lipid peroxidation. The elevated DNA fragmentation may be related with increased oxidative stress. The skin is more sensitive to the effects of L. major infection on oxidative stress induction compared to the lung

Comparison of antioxidant properties of N- acetylcysteine and vitamins E and C on diazinon-induced oxidative stress in rat spleen

Background and Aim: Organophosphate insecticides such as diazinon (DZN) can disrupt the body's antioxidant defense system. Antioxidants protect cells against oxidative stress. In the present study, antioxidant properties of N- acetylcysteine (NAC) and vitamins E and C in reducing oxidative stress caused by DZN in rat spleen were compared. Materials and Methods: In this experimental study,48 male Wistar rats were randomly divided into eight equal groups including. control ., DZN (100 mg/kg), NAC (160 mg/kg), vitamin E (150 mg/kg), vitamin C (200 mg/kg), NAC+DZN, vitamin E+DZN, and vitamin C+DZN groups. Twenty-four hours after intraperitoneal injection.the animals were anesthetized and their spleen tissues were quickly removed. After tissues&rsquo; hemogenation superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST) ,lactate dehydrogenase activities, as well as glutathione (GSH) and malondialdehyde levels were determined using biochemical methods. Results: DZN increased SOD and GST activities , but it decreased CAT activity and GSH content in the spleen. Administration of the antioxidant NAC or vitamin E caused SOD and GAT improvement. Conclusion: DZN induces oxidative stress in the spleen. NAC ,through increasing the synthesis of GSH , vitamins E ,and C- by removing free radicals- reduce DZN-induced oxidative stress. Comparing the effects of these antioxidants on GSH and GST activity indicates that the antioxidant value of NAC is greater than vitamins E and C