This review summarizes our findings concerning the altered balance of vasoactive systems (namely sympathetic nervous system and nitric oxide) in various forms of experimental hypertension – genetic hypertension (SHR, HTG rats), salt hypertension (Dahl rats) and NO-deficient hypertension (L-NAME-treated rats). An attempt is made to define relative NO deficiency (compared to the existing level of sympathetic vasoconstriction), to describe its possible causes and to evaluate particular indicators of its extent. A special attention is paid to reactive oxygen species, their interaction with NO metabolism, cell Ca2+ handling and blood pressure regulation. Our current effort is focused on the investigation of abnormal regulation of cytosolic Ca2+ levels in smooth muscle and endothelium of hypertensive animals. Such a research should cl
arify the mechanisms by which genetic and/or environmental factors could chronically modify blood pressure level.
Open heart surgery with a cardiopulmonary bypass (CPB) is associated with a systemic inflammatory response which significantly contributes to adverse postoperative complications. The purpose of this study was to characterize the activation of blood phagocytes during open heart surgery with CPB. Blood samples were collected during and up to 24 h after surgery. The production of reactive oxygen species (ROS) in whole blood, the expression of surface molecules by blood phagocytes and complement activity in the plasma were determined. A cDNA microarray analysis of leukocyte RNA profile of genes was performed related to the inflammatory response. Activation of the complement was already observed at the beginning of CPB. This was followed by an increase in the neutrophil number and in both spontaneous and opsonized zymosan-activated ROS production after the onset of reperfusion. The activation of blood phagocytes was affirmed by changes in surface receptors involved in the adhesion and migration of leukocytes (CD11b, CD62L and CD31). Gene arrays also confirmed the activation of leukocytes 4 h after reperfusion. In conclusion, open heart surgery with a cardiopulmonary bypass was found to be associated with a rapid and pronounced activation of blood phagocytes and complement activation which was partly independent at the onset of CPB.
Exercise increases the production of reactive oxygen species, which may damage a number of cell constituents. Organisms have developed a sophisticated antioxidant system for protection against reactive oxygen species. Our aim was to compare the adaptive responses of antioxidant mechanisms and the blood redox status of two groups of athletes, long-distance and short-distance runners. Thiobarbituric acid reactive substances, catalase activity and total antioxidant capacity was measured in the serum, while reduced and oxidized glutathione as well as their ratio were determined in blood hemolysates. Serum catalase activity (P<0.001) was found to be three times higher in long-distance compared to short-distance runners (25.4 vs. 8.9 μmol · min-1 ·ml-1), whereas the two groups did not differ in the other markers. Catalase activity also correlated significantly with maximal oxygen consumption in long-distance runners. In conclusion, we report here that long-distance and short-distance runners exhibit similar blood redox status judged by several oxidative stress indices, except for the much higher activity of catalase in long-distance runners. This different effect of the two training modules on catalase activity of long-distance runners might be partly due to the high oxygen load imposed during their repeated prolonged exercise bouts.
To predict more precisely the effect of stobadine, a pyridoindole antioxidant agent, in the whole organism, we studied its effect on opsonized zymosan-stimulated free radical generation in whole blood, on superoxide generation in the mixture of PMNL : platelets (1:50), as well as on superoxide generation and myeloperoxidase release in isolated PMNL. Without stimulation, stobadine had no effect on reactive oxygen species (ROS) generation and myeloperoxidase release. Stobadine in a concentration of 10 or 100 µmol/l significantly decreased luminol-enhanced chemiluminescence in opsonized zymosan-stimulated whole blood. In concentrations of 10 and 100 µmol/l, it reduced myeloperoxidase release from isolated neutrophils. Stobadine significantly decreased superoxide generation in isolated neutrophils in 100 µmol/l concentration. Its effect was much less pronounced in the mixture of neutrophils and platelets in the ratio close to physiological conditions (1:50). Our results suggest that stobadine might exert a beneficial effect in diseases or states where superfluous ROS generation could be deleterious.
Instead of a comprehensive review, we describe the basic undisputed facts and a modest contribution of our group to the fascinating area of the research on mitochondrial uncoupling proteins. After defining the terms uncoupling, leak, protein-mediated uncoupling, we discuss the assumption that due to their low abundance the novel mitochondrial
uncoupling proteins (UCP2 to UCP5) can provide only a mild uncoupling, i.e. can decrease the proton motive force by several mV only. Contrary to this, the highly thermogenic role of UCP1 in brown adipose tissue is not given only by its high content (~5 % of mitochondrial proteins) but also by the low ATP synthase content and high capacity respiratory chain. Fatty acid cycling mechanism as a plausible explanation for the protonophoretic function of all UCPs and some other mitochondrial carriers is described together with th
e experiments supporting it. The phylogenesis of all UCPs, estimated UCP2 content in several tissues, and details of UCP2 activation are described on the basis of our experiments. Functional activation of UCP2 is proposed to decrease reactive oxygen species (ROS) production. Moreover, reaction
products of lipoperoxidation such as cleaved hydroperoxy-fatty acids and hydroxy-fatty acid can activate UCP2 and promote feedback down-regulation of mitochondrial ROS production.
The purpose of this study is to analyze the protective effect of combining N-acetylcysteine (NAC) and hyberbaric oxygen (HBO) treatment in the lung tissue during acute pancreatitis. Sixty Sprague-Dawley male rats were randomly divided into five groups; Group I; Control group (n=12), Gr
oup II; pancreatitis group (n=12), Group III; pancreatitis +
NAC treatment group (n=12), Group IV; pancreatitis + HBO treatment group (n=12), Group V; pancreatitis + HBO + NAC treatment group (n=12). HBO was applied postoperatively for 5 days, twice a day at 2.5 fold absolute atmospheric pressure for 90 min. Lung tissue was obtained for measuring malondialdehyde (MDA), superoxide dismutase (Cu/Zn-SOD) and glutathione peroxidase (GSH-Px) levels along with histopathological tissue examinations. This study showed that all three treated groups (HBO alone, NAC alone
and combined HBO+NAC treatment) had pulmonary protective effects during acute necrotizing pancreatitis.
The purpose of this study was to follow up the changes in antioxidative adaptive mechanisms induced by various periods of small intestinal ischemia in Wistar rats. The superior mesenteric artery was occluded for 15, 30, 45, 60 and 90 min. After the respective ischemic intervals, a reperfusion was set for 120 min. Samples of the serum and intestinal mucosa were taken at the end of ischemia or at the end of reperfusion. Total radical-trapping antioxidant parameter (TRAP) of the serum and the oxidative burst of neutrophils were evaluated using luminol-enhanced chemiluminescence. Individual antioxidants in the serum and the concentration of thiobarbituric acid reactive substances (TBARs) in both serum and intestinal mucosa were measured spectrophotometrically. Increased activation of circulating neutrophils was found after the reperfusion irrespective of the duration of ischemia. TRAP of the serum was increased at the end of the ischemia lasting from 30 to 90 min. This effect was further enhanced by the subsequent reperfusion period. Ascorbate and urate contributed considerably to the TRAP value especially after reperfusion following 60 and 90 min of ischemia. On the other hand, no significant changes in albumin and bilirubin serum concentrations were observed. Contrary to the mobilized antioxidative mechanisms, increased lipid peroxidation was observed in both serum and mucosa samples.
Brain infections as well as peripheral challenges to the immune system lead to an increased production of interleukin-1beta (IL-1b), a cytokine involved in leukocyte-mediated breakdown of the blood-brain barrier. The effects of IL-1b have been reported to depend on whether the route of administration is systemic or intracerebral. Using 50-day-old male rats, we compared the effects of IL-1b on brain γ-glutamyl transpeptidase (GGT; an enzymatic marker of brain capillary endothelium) at 2, 24 and 96 h after either an intravenous (i.v.) injection of 5 μg IL-1β or an intracerebroventricular (i.c.v. - lateral ventricle) infusion of 50 ng IL-1β. When the i.v. route was used, the GGT activity underwent small but significant changes; decreasing in the hippocampus 2 h after the i.v. injection, increasing 24 h later and returning to control levels at 96 h. No significant changes in the hippocampal GGT activity were observed at 2 and 24 h following the i.c.v. infusion. The GGT activity in the hypothalamus remained unchanged regardless of the route of IL-1b administrations. Similar changes in GGT activity were revealed histochemically. The labeling was found mainly in the capillary bed, the changes being most evident in the hippocampal stratum radiatum and stratum lacunosum-moleculare. A transient increase in GGT activity at 24 h, together with a less sharp delineation of GGT-stained vessels, may reflect IL-1b induced increased turnover of glutathione and/or oxidative stress, that may in turn, be related to altered permeability of the blood-brain barrier in some neurological and mental disorders, including schizophrenia.
Autophagy is implicated in the maintenance of cardiac homeostasis. Autophagy is activated in heart failure, in which reactive oxygen species (ROS) are increased. Exogenous ROS have been shown to induce cardiomyocyte autophagy alterations. However, little is known about the influences of physiological levels of endogenous ROS on cardiomyocyte autophagy. In the present study, we tested the hypothesis that endogenous ROS in cardiomyocytes play an important role in inducing autophagy. Cultured H9C2 cardiomyocytes or Sprague-Dawley rats were treated with the antioxidant N-acetyl-cysteine (NAC) or the superoxide dismutase mimic tempol under the basal or nutrient deprivation conditions. The autophagic flux was assessed by the lysosomal inhibitor chloroquine. In H9C2 cardiomyocytes, under a basal condition, NAC or tempol increased the ratio of LC3 II/I proteins and reduced LC3 II autophagic flux. Under nutrient deprivation, NAC increased the LC3 II/I ratio and reduced LC3 II autophagic flux. In vivo studies in rats, NAC treatment increased the LC3 II/I ratio and p-Akt protein expression in myocardium. We concluded that the antioxidants reduced autophagic flux in cardiomyocytes under the basal or nutrient deprivation conditions, suggesting that endogenous ROS promote autophagy flux under physiological conditions, and this effect is mediated, at least in part, through Akt inhibition., J.-P. Wang, R.-F. Chi, J. Liu, Y.-Z. Deng, X.-B. Han, F.-Z. Qin, B. Li., and Seznam literatury