BACKGROUND: AGE-induced oxidative stress is implicated in the development and progression of diabetic nephropathy. AGE also affect the GEC to increase their permeability, therefore, we investigate the possibility that AGE may induce oxidative stress and subsequent injury to GEC. METHODS: We cultured rat GEC on the AGE- or BSA-coated plate with high glucose (HG) to produce more pathophysiologic conditions similar to prolonged diabetic environment in vivo and measured the change of ROS and their anti-oxidants systems. We also evaluated the effects of probucol as an antioxidant on this system. RESULTS: The amount of superoxide anion slightly decreased on AGE condition without significance. However, the production of hydrogen peroxide was significantly enhanced by 10% on AGE-coated and HG condition compared to control (BSA-coated and 5 mM glucose) (p< 0.05) and hydroxyl radical have also showed similar increase on AGE-coated and HG condition by 10% above control (p< 0.01), and both increases were attenuated by probucol (both, p< 0.05). The activity of superoxide dismutase (SOD) was decreased by 10% on AGE-coated and HG condition (p< 0.05) and recovered by probucol partially. However, there were no significant changes on the activity of other anti-oxidant enzymes including catalase, glutathione peroxidase, and glutathione reductase. Therefore, glomerular epithelial injury presenting proteinuria may be provoked by hydrogen peroxide and subsequently increased hydroxyl radical induced by AGE and high glucose. CONCLUSION: We might assume that superoxide had been converted to hydrogen peroxide by consumptive SOD in the presence of AGE, and subsequently produced hydroxyl radical, which could be reversed by anti-oxidant, may induce diabetic glomerular epithelial injury and eventually proteinuria.
Animals ; Catalase ; Diabetic Nephropathies ; Epithelial Cells* ; Glucose ; Glutathione Peroxidase ; Glutathione Reductase ; Hydrogen Peroxide ; Hydroxyl Radical ; Oxidative Stress ; Permeability ; Probucol ; Proteinuria ; Rats* ; Reactive Oxygen Species* ; Superoxide Dismutase ; Superoxides

6'-O-galloylpaeoniflorin (GPF) is a galloylated derivate of paeoniflorin and a key chemical constituent of the peony root, a perennial flowering plant that is widely used as an herbal medicine in East Asia. This study is the first investigation of the cytoprotective effects of GPF against hydrogen peroxide (H2O2)-induced cell injury and death in human HaCaT keratinocytes. GPF demonstrated a significant scavenging capacity against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, H2O2-generated intracellular reactive oxygen species (ROS), the superoxide anion radical (O2-), and the hydroxyl radical (*OH). GPF also safeguarded HaCaT keratinocytes against H2O2-provoked apoptotic cell death and attenuated oxidative macromolecular damage to DNA, lipids, and proteins. The compound exerted its cytoprotective actions in keratinocytes at least in part by decreasing the number of DNA strand breaks, the levels of 8-isoprostane (a stable end-product of lipid peroxidation), and the formation of carbonylated protein species. Taken together, these results indicate that GPF may be developed as a cytoprotector against ROS-mediated oxidative stress.
Cell Death ; DNA ; Far East ; Flowers ; Herbal Medicine ; Humans* ; Hydrogen Peroxide ; Hydroxyl Radical ; Keratinocytes* ; Oxidative Stress ; Paeonia ; Plants ; Reactive Oxygen Species ; Superoxides

Ischemia followed by reperfusion in the presence of polymorphonuclear leukocytes (PMNs) results in a marked cardiac contractile dysfunction. Amrinone, a specific inhibitor of phosphodiesterase 3, has an antioxidant activity against PMNs. Therefore, we hypothesized that amrinone could attenuate PMNs-induced cardiac dysfunction by suppression of reactive oxygen species (ROS) produced fby PMNs. In the present study, we examined the effects of amrinone on isolated ischemic (20 min) and reperfused (45 min) rat hearts perfused with PMNs. Amrinone at 25microM, given to hearts during the first 5 min of reperfusion, significantly improved coronary flow, left ventricular developed pressure (P< 0.001), and the maximal rate of development of left ventricular developed pressure (P< 0.001), compared with ischemic/reperfused hearts perfused with PMNs in the absence of amrinone. In addition, amrinone significantly reduced myeloperoxidase activity by 50.8%, indicating decreased PMNs infiltration (p< 0.001). Superoxide radical and hydrogen peroxide production were also significantly reduced in fMLP- and PMA-stimulated PMNs pretreated with amrinone. Hydroxyl radical was scavenged by amrinone. fMLP-induced elevation of [Ca2+]i was also inhibited by amrinone. These results provide evidence that amrinone can significantly attenuate PMN-induced cardiac contractile dysfunction in the ischemic/ reperfused rat heart via attenuation of PMNs infiltration into the myocardium and suppression of ROS release by PMNs.
Amrinone* ; Animals ; Cyclic Nucleotide Phosphodiesterases, Type 3* ; Heart ; Hydrogen Peroxide ; Hydroxyl Radical ; Ischemia ; Myocardium ; Neutrophils ; Peroxidase ; Rats ; Reactive Oxygen Species ; Reperfusion ; Superoxides

The patients with end stage renal disease show several complications such as artherosclerosis, anemia and increased susceptibility to infection by damage due to oxygen free radicals. Superoxide dismutase(SOD) is directly linked to the fate of the highly reactive oxygen metabolites. If there is an alteration in the activity of SOD, this alteration may contribute to the complications by reactive oxygen species in patients with end stage renal disease. In this experiment, SOD activity and the effect of cyanate on the activity of SOD was studied to understand the mechanism of several complications mediated by oxygen free radicals in patients with end stage renal disease. SOD activity in the plasma and erythrocytes from patients with end stage renal disease was significantly lower than those from healthy controls. It is known that underproduction of SOD leads to excess production of superoxide and reduced iron favoring hydroxyl radical formation. The results in this experiment suggest that there is an overproduction of superoxide anion in patients with end stage renal disease. The overproduction of superoxide anion may contribute the patients with end stage renal disease susceptible to oxidant damages. To evaluate if cyanate could carbamylate SOD, SOD was incubated with cyanate. The level of carbamylated SOD increased as the time of exposure to cyanate increased from 0 hour to 72 hours. Furthermore, the degree of carbamylation of SOD increased as cyanate concentration in the incubation media rose from 20mM to 1M. There appears to be a maximum degree of carbamylation at a concentration of 1,000mM cyanate. To test the hypothesis that in vitro carbamylation of SOD alters its biological activity, SOD activity was measured after incubation with cyanate. The activity of carbamylated SOD decreased as the time of exposure to cyanate increased from 0 hour to 72 hours. Furthermore, the activity of carbamylated SOD decreased as cyanate concentration in the incubation media rose from 20mM to 1M and when albumin was added to the reaction mixture, the loss of SOD activity was prevented. These results are consistent with the hypothesis that SOD is also carbamylated and lost biological activity in end stage renal disease patients by cyanate, and that the degree of carbamylation depends on both the concentration of cyanate and the length of exposure. Also, these suggest that albumin may prevent carbamylation of SOD at least in vitro condition.
Anemia ; Erythrocytes ; Free Radicals ; Humans ; Hydroxyl Radical ; Iron ; Kidney Failure, Chronic ; Oxygen ; Plasma ; Reactive Oxygen Species ; Superoxide Dismutase* ; Superoxides* ; Uremia

Reactive oxygen species (ROS) are generated in various cells, including vascular smooth muscle and endothelial cells, and regulate ion channel functions. KCa3.1 plays an important role in endothelial functions. However, the effects of superoxide and hydrogen peroxide radicals on the expression of this ion channel in the endothelium remain unclear. In this study, we examined the effects of ROS donors on KCa3.1 expression and the K+ current in primary cultured human umbilical vein endothelial cells (HUVECs). The hydrogen peroxide donor, tert-butyl hydroperoxide (TBHP), upregulated KCa3.1 expression, while the superoxide donors, xanthine/xanthine oxidase mixture (X/XO) and lysopho-sphatidylcholine (LPC), downregulated its expression, in a concentration-dependent manner. These ROS donor effects were prevented by antioxidants or superoxide dismustase. Phosphorylated extracellular signal-regulated kinase (pERK) was upregulated by TBHP and downregulated by X/XO. In addition, repressor element-1-silencing transcription factor (REST) was downregulated by TBHP, and upregulated by X/XO. Furthermore, KCa3.1 current, which was activated by clamping cells with 1 microM Ca2+ and applying the KCa3.1 activator 1-ethyl-2-benzimidazolinone, was further augmented by TBHP, and inhibited by X/XO. These effects were prevented by antioxidants. The results suggest that hydrogen peroxide increases KCa3.1 expression by upregulating pERK and downregulating REST, and augments the K+ current. On the other hand, superoxide reduces KCa3.1 expression by downregulating pERK and upregulating REST, and inhibits the K+ current. ROS thereby play a key role in both physiological and pathological processes in endothelial cells by regulating KCa3.1 and endothelial function.
Antioxidants ; Benzimidazoles ; Constriction ; Endothelial Cells ; Endothelium ; Hand ; Human Umbilical Vein Endothelial Cells ; Humans ; Hydrogen ; Hydrogen Peroxide ; Ion Channels ; Muscle, Smooth, Vascular ; Oxidoreductases ; Pathologic Processes ; Phosphotransferases ; Reactive Oxygen Species ; Superoxides ; tert-Butylhydroperoxide ; Tissue Donors ; Transcription Factors

Antioxidants oppose the toxic actions of lipid peroxides and oxygen radicals, and they limit the amount of lipid peroxides formed. Women with normal pregnancies have an increase in oxidative stress and lipid peroxidation when compared with nonpregnant women. The antioxidants also increase progressively with advancing gestation, and the antioxidants in the fetus also increase with advancing gestation, especially during late gestation. The purpose of this study is to investigate the diefference of antioxidant status in maternal and neonatal plasma according to the delivery type. So, we investigated the status of antioxidant in the maternal and neonatal plasma when compared normal vaginal delivery with Cesarian section without labor. This study was done under the hypothesis that labor pain is originated from the hypoxic state of myometrium during uterine contraction. The number of women who were studied was total 56, 24 women were delivered by normal vaginal delivery and 32 women were done by Cesarean section without labor. The blood was sampled during active labor and postpartum 24 hour in the case of normal vaginal delivery, the women who were done Cesarean section being sampled before operation and 24 hours after operation. The neonatal blood was sampled from cord, birth 1 day and 3 day. The antioxidant levels were measured by Total Antioxidant Status (Randox Laboratory Ltd., UK) kit. The results were as follows. 1. The mean maternal plasma antioxidant status was not significantly different according to delivery types and not significantly different when compared antepartum with postpartum (vaginal delivery; antepartum: 1.54+/-0.31 mM/L, postpartum: 1.58+/-0.32 mM/L, Cesarean section; antepartum: 1.55+/-0.29 mM/L, postpartum: 1.56+/-0.33 mM/L). 2. The neonatal antioxidant status was not significantly different between the neonates who were born by vaginal delivery and the neonates who were born by Cesarean section. The neonatal plasma antioxidant status was increased progressively after birth (cord: birth 1 day: birth 3 day=1.46+/-0.25 mM/L: 1.59+/-0.25 mM/L: 1.79+/-0.37 mM/L). Therefore, labor pain was not seems to be significantly affect the maternal and neonatal plasma antioxidant status. And the neonatal antioxidant status was increased for adaptation to the external environment after birth.
Animals ; Antioxidants ; Cesarean Section ; Female ; Fetus ; Humans ; Infant, Newborn ; Labor Pain ; Lipid Peroxidation ; Lipid Peroxides ; Mice ; Myometrium ; Oxidative Stress ; Parturition ; Plasma* ; Postpartum Period ; Pregnancy ; Reactive Oxygen Species ; Toxic Actions ; Uterine Contraction

This study was aimed at evaluating the effect of defibrotide on the development of the surgically induced reflux esophagitis, on gastric secretion, lipid peroxidation, polymorphonuclear leukocytes (PMNs) accumulation, polymorphonuclear leukocytes adherence, superoxide anion and hydrogen peroxide production in PMNs, scavenge of hydroxyl radical and hydrogen peroxide, cytokine (interleukin-1beta, tumor necrosis factor-alpha) production in blood, and intracellular calcium mobilization in PMNs. Defibrotide did not inhibit the gastric secretion and not change the gastric pH. Treatment of esophagitis rats with defibrotide inhibited lipid peroxidation, and myeloperoxidase (MPO) in the esophagus in comparison with untreated rats. Defibrotide significantly decreased the PMN adherence to superior mesenteric artery endothelium in a dose-dependent manner. Superoxide anion and hydrogen peroxide production in 1microM formylmethionylleucylphenylalanine (fMLP) - or 0.1microgram/ml N-phorbol 12- myristate 13-acetate (PMA) -activated PMNs was inhibited by defibrotide in a dose-dependent fashion. Defibrotide effectively scavenged the hydrogen peroxide but did not scavenge the hydroxyl radical. Treatment of esophagitis rats with defibrotide inhibited interleukin-1beta production in the blood in comparison with untreated rats, but tumor necrosis factor-alpha production was not affected by defibrotide. The fMLP-induced elevation of intracellular calcium in PMNs was inhibited by defibrotide. The results of this study suggest that defibrotide may have partly beneficial protective effects against reflux esophagitis by the inhibition lipid peroxidation, PMNs accumulation, PMNs adherence to endothelium, reactive oxygen species production in PMNs, inflammatory cytokine production (i.e. interleukin-1beta), and intracellular calcium mobilization in PMNs in rats.
Animals ; Calcium ; Endothelium ; Esophagitis ; Esophagitis, Peptic* ; Esophagus ; Hydrogen Peroxide ; Hydrogen-Ion Concentration ; Hydroxyl Radical ; Interleukin-1beta ; Lipid Peroxidation ; Mesenteric Artery, Superior ; Myristic Acid ; N-Formylmethionine Leucyl-Phenylalanine ; Necrosis ; Neutrophils ; Peroxidase ; Rats* ; Reactive Oxygen Species ; Superoxides ; Tumor Necrosis Factor-alpha

Preterm infants are vulnerable to the oxidative stress due to the production of large amounts of free radicals, antioxidant system insufficiency, and immature oligodendroglial cells. Reactive oxygen species (ROS) play a pivotal role in the development of periventricular leukomalacia. The three most common ROS are superoxide (O2*-), hydroxyl radical (OH*), and hydrogen peroxide (H2O2). Under normal physiological conditions, a balance is maintained between the production of ROS and the capacity of the antioxidant enzyme system. However, if this balance breaks down, ROS can exert toxic effects. Superoxide dismutase, glutathione peroxidase, and catalase are considered the classical antioxidant enzymes. A recently discovered antioxidant enzyme family, peroxiredoxin (Prdx), is also an important scavenger of free radicals. Prdx1 expression is induced at birth, whereas Prdx2 is constitutively expressed, and Prdx6 expression is consistent with the classical antioxidant enzymes. Several antioxidant substances have been studied as potential therapeutic agents; however, further preclinical and clinical studies are required before allowing clinical application.
Antioxidants ; Brain ; Brain Injuries ; Catalase ; Free Radicals ; Glutathione Peroxidase ; Humans ; Hydrogen Peroxide ; Hydroxyl Radical ; Infant, Newborn ; Infant, Premature ; Leukomalacia, Periventricular ; Oxidative Stress ; Parturition ; Peroxiredoxins ; Reactive Oxygen Species ; Superoxide Dismutase ; Superoxides

Reactive oxygen species (ROS), which include hydrogen peroxide (H2O2), the superoxide anion (O2-.), and the hydroxyl radical (OH.), are generated as by-products of oxidative metabolism in cells. The cerebral cortex has been found to be particularly vulnerable to production of ROS associated with conditions such as ischemia-reperfusion, Parkinson's disease, and aging. To investigate the effect of ROS on inhibitory GABAergic synaptic transmission, we examined the electrophysiological mechanisms of the modulatory effect of H2O2 on GABAergic miniature inhibitory postsynaptic current (mIPSCs) in mechanically isolated rat cerebral cortical neurons retaining intact synaptic boutons. The membrane potential was voltage-clamped at -60 mV and mIPSCs were recorded and analyzed. Superfusion of 1-mM H2O2 gradually potentiated mIPSCs. This potentiating effect of H2O2 was blocked by the pretreatment with either 10,000-unit/mL catalase or 300-micrometer N-acetyl-cysteine. The potentiating effect of H2O2 was occluded by an adenylate cyclase activator, forskolin, and was blocked by a protein kinase A inhibitor, N-(2-[p-bromocinnamylamino] ethyl)-5-isoquinolinesulfonamide hydrochloride. This study indicates that oxidative stress may potentiate presynaptic GABA release through the mechanism of cAMP-dependent protein kinase A (PKA)-dependent pathways, which may result in the inhibition of the cerebral cortex neuronal activity.
Adenylyl Cyclases ; Aging ; Animals ; Catalase ; Cerebral Cortex ; Cyclic AMP-Dependent Protein Kinases ; Forskolin ; gamma-Aminobutyric Acid ; Hydrogen Peroxide ; Hydroxyl Radical ; Inhibitory Postsynaptic Potentials ; Membrane Potentials ; Neurons ; Oxidative Stress ; Parkinson Disease ; Presynaptic Terminals ; Rats ; Reactive Oxygen Species ; Superoxides ; Synaptic Transmission

This study was designed to investigate the effects of pyroligneous liquor on oxygen radicals and their scavenger enzy-mes in the liver of Cri/Bgi CD rats (7 rats per group ). Male rats were fed a basic diet prepared in our Lab., PL-0 (Control ), PL-1, PL-25, PL-50 and PL-75 groups were prepared to be 0%, 1%, 25%, 50% and 75%with distilled water using pyrolig-neous liquor (35% of Choa Co. Ltd.), and were administrated orally for 8 weeks. Superoxide radical contents in liver mi-tochondria and microsomes were significantly decreased to 12-14%, 11-15%, respectively, in these PL-25 and PL-50 groups compared with the control group. Hydroxyl radical content in mitochondria and microsomes were markedly decreased to 12-20% and 17%, respectively, in these PL-25 and PL-50% groups compared with the control group. Hydro-gen peroxide content in mitochondria and microsomes were significantly decreased about 15-12% and 22-20% in liver of PL-25 and PL-50 groups compared with the control group. Mn-SOD and Cu/Zn-SOD activities in liver of PL-25 and PL-50 groups were remarkably increased to 15-25%, 11-16%, respectively, compared with the control group. GPx activities in mitochondria and microsomes were significantly increased in the liver of PL-25 and PL-50 groups compared with the control group. CAT activities in mitochondria and cytosol were significantly increased to 12-14%, 15-27%, respectively, in the liver of PL-25 and PL-50 groups compared with the control group. These results suggest that long term administra-tion orally of 25 and 50% pyroligneous liquor may effectively inhibit the formation of oxygen free radicals, and also scavenger enzyme activities significantly increase through the administration orally.
Animals ; Cats ; Cytosol ; Diet ; Free Radicals ; Humans ; Hydroxyl Radical ; Liver* ; Male ; Microsomes ; Mitochondria ; Oxygen* ; Rats* ; Reactive Oxygen Species* ; Superoxide Dismutase ; Superoxides ; Water