ascorbic-acid and Ischemia

Preeclampsia, intrauterine growth restriction (IUGR), and placental abruption are obstetrical conditions that constitute the syndrome of ischemic placental disease or IPD, the leading cause of indicated preterm birth and an important cause of neonatal morbidity and mortality. While the phenotypic manifestations vary significantly for preeclampsia, IUGR, and abruption, these conditions may share a common underlying etiology as evidenced by: (1) shared clinical risk factors, (2) increased recurrence risk across pregnancies as well as increased co-occurrence of IPD conditions within a pregnancy, and (3) findings that suggest the underlying pathophysiologic processes may be similar. IPD is of major clinical importance and accounts for a large proportion of indicated preterm delivery ranging from the periviable to late preterm period. Successful prevention of IPD and resultant preterm delivery could substantially improve neonatal and maternal outcomes. This article will review the following topics: (1) The complicated research literature on aspirin and the prevention of preeclampsia and IUGR. (2) Research evidence on other medical interventions to prevent IPD. (3) New clinical interventions currently under investigations, including statins. (4) Current clinical recommendations for prevention of ischemic placental disease.

Topics: Abruptio Placentae; Anticoagulants; Ascorbic Acid; Aspirin; Calcium, Dietary; Dietary Supplements; Fatty Acids, Omega-3; Female; Fetal Growth Retardation; Fibrinolytic Agents; Humans; Ischemia; Placenta; Placenta Diseases; Pre-Eclampsia; Pregnancy; Premature Birth; Risk Factors; Vitamin E

Ascorbate (vitamin C) is a vital antioxidant molecule in the brain. However, it also has a number of other important functions, participating as a cofactor in several enzyme reactions, including catecholamine synthesis, collagen production, and regulation of HIF-1 alpha. Ascorbate is transported into the brain and neurons via the sodium-dependent vitamin C transporter 2 (SVCT2), which causes accumulation of ascorbate within cells against a concentration gradient. Dehydroascorbic acid, the oxidized form of ascorbate, is transported via glucose transporters of the GLUT family. Once in cells, it is rapidly reduced to ascorbate. The highest concentrations of ascorbate in the body are found in the brain and in neuroendocrine tissues such as adrenal, although the brain is the most difficult organ to deplete of ascorbate. Combined with regional asymmetry in ascorbate distribution within different brain areas, these facts suggest an important role for ascorbate in the brain. Ascorbate is proposed as a neuromodulator of glutamatergic, dopaminergic, cholinergic, and GABAergic transmission and related behaviors. Neurodegenerative diseases typically involve high levels of oxidative stress and thus ascorbate has been posited to have potential therapeutic roles against ischemic stroke, Alzheimer's disease, Parkinson's disease, and Huntington's disease.

Topics: Animals; Antioxidants; Ascorbic Acid; Biological Transport; Brain; Humans; Ischemia; Neurodegenerative Diseases; Neurons; Organic Anion Transporters, Sodium-Dependent; Oxidative Stress; Sodium-Coupled Vitamin C Transporters; Symporters; Synaptic Transmission

NMDA receptors play a central role in neuronal plasticity and in several pathological situations. Transient activation of this receptor triggers long-term potentiation, whereas sustained activation leads to cell death. Evidence for control of this activity by a redox site in cell cultures, brain tissues and in recombinant NMDA receptors are discussed by Henri Gozlan and Yehezkel Ben-Ari. The characteristics of this modulation and the consequences of redox state modifications on NMDA-mediated events are examined in vitro under physiological and pathological conditions. Since metabolic disorders enhance NMDA receptor function, the redox site could constitute a new target for selectively preventing in vivo the deleterious consequences of overactivation without blocking neuronal plasticity mediated by NMDA receptors.

Topics: Alkylation; Animals; Ascorbic Acid; Brain; Cells, Cultured; Epilepsy; Free Radicals; In Vitro Techniques; Ischemia; Neuronal Plasticity; Oxidation-Reduction; Receptors, N-Methyl-D-Aspartate; Recombinant Proteins; Sulfhydryl Compounds; Sulfhydryl Reagents; Synaptic Transmission; Xenopus laevis

In summary, much evidence supports the formation of toxic oxygen metabolites in ischemic reperfused tissue. Tissues are equipped with both an intracellular and extracellular antioxidant defense system. The defense system can also be divided into enzymatic and nonenzymatic defenses. Important components of a nonenzymatic antioxidant include alpha-tocopherol, ascorbic acid, and beta-carotene as well as other compounds that can react with radicals to form less reactive products such as sulfur-containing amino acids. Extracellular fluid comprises a second line of defense against oxidant injury. These extracellular antioxidants include ceruloplasmin, albumin, transferrin, haptoglobin, and uric acid. The oxidant injury can potentially occur during ischemia and reperfusion due to (1) an excess production of oxygen free radicals, (2) a decrease in antioxidant defenses, or (3) both. Because antioxidants function by removing the toxic oxygen metabolites, they are generally highly effective in reducing ischemia-reperfusion injury.

Topics: Animals; Antioxidants; Ascorbic Acid; beta Carotene; Carotenoids; Free Radicals; Humans; Ischemia; Oxidants; Reperfusion Injury; Vitamin E

Free radical (FR) mechanisms have both beneficial and deleterious actions in vivo. Intensive scientific interest in FRs over the last 20 years has led to a clearer understanding of their roles and helped to clarify the contribution of our intrinsic defence systems (antioxidants) in limiting FR-induced tissue damage. As more and more conditions are shown to have a FR aetiology it becomes imperative to develop newer therapies to prevent and treat FR-induced disease.

Topics: Antioxidants; Ascorbic Acid; Chemical Phenomena; Chemistry; Free Radicals; Humans; Ischemia; Lipid Peroxidation; Phagocytosis; Superoxide Dismutase; Vitamin E

In light of the current methodological developments in flow-mediated dilation (FMD) testing and the recognition that oxidative stress may play an important role in regulating this process, the present study sought to: (1) compare flow-mediated dilation (FMD) following 5 and 10 min of forearm cuff occlusion, and (2) evaluate the role of oxidative stress on vasodilation, both distal and proximal to the cuff. Of the 14 subjects studied, 6 partook solely in a validation study of the antioxidant cocktail (AOC; vitamins C, E, and alpha-lipoic acid), while the remaining 8 subjects underwent FMD assessment in response to 5 and 10 min of forearm occlusion following ingestion of AOC or placebo. Although the efficacy of the AOC was clearly documented by elevated plasma ascorbate levels (approximately 95%) and a reduced free radical concentration (approximately 65%), no effects of acute oral antioxidants were observed. FMD was significantly augmented in response to 10 min of forearm occlusion when compared to 5 min, whether expressed as % change (10.1 +/- 2 vs. 4.5 +/- 1%, respectively) or absolute change in diameter (0.035 +/- 0.005 vs. 0.018 +/- 0.005 cm, respectively). Additionally, post-occlusion shear rate (28,640 +/- 2,799 vs. 18,629 +/- 1,724/s, AUC), FMD/shear rate (approximately 50%), and time to peak dilation (68 +/- 7 vs. 53 +/- 8 s) were greater following 10 min of occlusion. In contrast to previous studies, this investigation has identified a greater brachial artery FMD in response to 10 versus 5 min of forearm ischemia, which appears to be unexplained by oxidative stress.

Topics: Administration, Oral; Adult; Antioxidants; Ascorbic Acid; Brachial Artery; Cross-Over Studies; Double-Blind Method; Humans; Hyperemia; Ischemia; Male; Placebos; Regional Blood Flow; Time Factors; Vasodilation; Young Adult

Testicular torsion is still an urgent surgical condition and without any treatment it can cause infertility. The main pathophysiology of testicular torsion ischaemic injury however; the main sequalae of detorsion is reperfusion injury. Furthermore; treatments to prevent ischemic reperfusion injury due to decreased blood flow are important to preserve testicular function.. Human chorionic gonadotropin β (β-hCG) is an anabolic hormone that supports steroidogenesis and spermatogenesis. Vitamin C (Vit-C) is one of the water-soluble vitamins and is also a potent antioxidant in ischemic damage. Moreover, it has protective effects by increasing blood and lymph flow in the testicles. The aim of this study is to investigate the effects of β-hCG, Vit-C and their combination on ischemic reperfusion injury occurring after surgical treatment of testicular torsion.. Animal research studies.. The study was performed on 25 male Wistar albino rats. The animals were divided equally into 5 groups. In the first group "Control Group," left orchiectomy was performed. In the second group "Sham Group," a 720° clockwise torsion was created and after 4 h of left testicular torsion it was detorsioned for 4 h and then left orchiectomy was performed. In the third group same procedure was applied with 30 mg vitamin C was administered via intraperitoneal route once a week for 3 weeks. In the fourth group after same surgical procedures 75 IU β-hCG was administered via intraperitoneal route once a week for 3 weeks. In the fifth group after 4 h left testicle torsion it was detorsioned for 4 h then, 75 IU β-hCG and vitamin C together were administered via intraperitoneal route once a week for 3 weeks. Left orchiectomy was performed after 3 weeks in the third, fourth and fifth groups. Specimens were evaluated histologically.. Testicular tissue histopathological evaluations were performed. A high histopathological stage indicates more testicular damage, and a low one was indicated less testicular damage. The average histopathological grade of vitamin C + β-hCG group was significantly higher than the average histopathological grade of the control, the sham group and vitamin C group. The average histopathological grade of the vitamin C group was significantly lower than the average histopathological grade of sham and β-hCG groups. The ratio of the testicular atrophy of the Vitamin C + β-hCG group (100%) was higher than sham (40%) and β-hCG (40%) groups with a significant difference. A significant statistical difference was found among all groups histopathological grades of testicular tissue.. In animals taking vitamin C, an improvement of histopathological findings and a significant decrease in histological stages has been provided. However, it was observed that the histological findings of β-hCG and β-hCG + vitamin C groups worsened. It was found that β-hCG increased oxidative damage in the testicles and this damage can be so severe that exceeding the capacity of potent antioxidants such as Vitamin C. We believe that β-hCG can be harmful to testicles exposed to oxidative damage.

Topics: Animals; Antioxidants; Ascorbic Acid; Humans; Ischemia; Male; Rats; Rats, Wistar; Reperfusion Injury; Spermatic Cord Torsion; Testicular Diseases; Testis; Vitamins

Maintaining the redox balance of biological systems is a key point to maintain a healthy physiological environment. Excessive iron ions (Fe

Topics: Animals; Ascorbic Acid; Carbon; Cell Hypoxia; Deferoxamine; Fluorescent Dyes; Hep G2 Cells; Humans; Hypoxia; Iron; Ischemia; Limit of Detection; Liver; Mice, Inbred BALB C; Microscopy, Confocal; Microscopy, Fluorescence; Oxidative Stress; Quantum Dots; Zebrafish

Liver ischemia and reperfusion injury (IRI) is a major problem associated with liver surgery. This study is aimed to compare the preventive effect of an antioxidative nutrient-rich enteral diet (Ao diet) with an ordinal enteral diet (control diet) against liver IRI.. The Ao diet was an ordinary diet comprising polyphenols (catechin and proanthocyanidin) and enhanced levels of vitamins C and E. Male C57BL/6 mice were fed the Ao or control diet for 7 days before ischemic insult for 60 minutes, followed by reperfusion for 6 hours. The levels of inflammatory cytokines, chemokines, and antioxidant enzymes and oxidative stress were evaluated.. After 7 days of pretreatment with the Ao diet, the serum levels of vitamins C and E in mice were markedly elevated. The levels of serum aspartate aminotransferase and alanine aminotransferase, as well as the scores of liver necrosis caused by ischemia and reperfusion, were significantly lower in the Ao diet group than in the control diet group. The gene expression levels of inflammatory cytokines and chemokines, such as interleukin-6 and CXCL1, were significantly lower in the Ao diet group. In the liver, the levels of antioxidant enzymes superoxide dismutase 1 (SOD1) and SOD2 were significantly higher and the malondialdehyde levels were significantly lower in the Ao diet group. Cell adhesion molecule expression was significantly lower, and neutrophil and macrophage infiltration was less in the Ao diet group.. Antioxidative nutrient supplementation to an ordinary enteral diet may mitigate liver IRI by causing an antioxidant effect and suppressing inflammation.

Topics: Alanine Transaminase; Animals; Antioxidants; Ascorbic Acid; Aspartate Aminotransferases; Catechin; Diet; Digestive System Surgical Procedures; Enteral Nutrition; Food, Fortified; Ischemia; Liver; Liver Diseases; Male; Malondialdehyde; Mice, Inbred C57BL; Oxidative Stress; Plant Extracts; Proanthocyanidins; Reperfusion Injury; Superoxide Dismutase; Vitamin E

An ischemia/reperfusion injury of rat's sciatic nerve was experimentally developed. In this model, we measured the in vivo production of superoxide radical, as a marker of oxidative stress and the occludin expression as an indicator of blood-nerve barrier function and we examined potential protective innervations against these abnormalities. Right sciatic nerves of the animals underwent 3 h of ischemia followed by 7 days of reperfusion and were divided into three groups: ischemic, pretreated with vitamin C in conjunction with vitamin E and treated with tissue plasminogen activator. Compared to measurements from left sciatic nerves used as sham, the ischemic group showed significantly increased superoxide radical and reduced expression of occludin in western blot and immunohistochemistry. No such differences were detected between sham and nerves in the vitamin or tissue plasminogen activator groups. It is suggested that the experimental ischemia/reperfusion model was suitable for studying the relationship between oxidative state and blood-nerve barrier. The reversion of abnormalities by the applied neuroprotective agents might prove to be a clinically important finding in view of the implication of vascular supply derangement in various neuropathies in humans.

Topics: Animals; Ascorbic Acid; Ischemia; Male; Neuroprotective Agents; Oxidative Stress; Rats, Wistar; Reperfusion Injury; Sciatic Nerve; Tissue Plasminogen Activator; Vitamin D

A series of novel (1S)-(-)-verbenone derivatives was synthesized bearing a 4-styryl scaffold. The synthesized compounds were tested for their anti-oxidant, anti-excitotoxic, and anti-ischemic activities. These derivatives significantly reduced oxygen-glucose deprivation-induced neuronal injury and N-methyl-D-aspartic acid-evoked excitotoxicity in cortical neurons. Furthermore, compound 3f was identified as a potent anti-ischemic agent in an in vitro ischemic model, potentially due to the inhibition of N-methyl-D-aspartic acid-evoked excitotoxicity and oxidative/nitrosative stress.

Topics: Animals; Antioxidants; Bicyclic Monoterpenes; Cells, Cultured; Disease Models, Animal; Drug Discovery; Ischemia; N-Methylaspartate; Neurons; Neuroprotective Agents; Oxidative Stress; Terpenes

Nitric oxide (NO) derived from endothelial nitric oxide synthase (eNOS) is a potent vasodilator and signaling molecule that plays an essential role in vascular remodeling of collateral arteries and perfusion recovery in response to hindlimb ischemia. In ischemic conditions, decreased NO bioavailability was observed because of increased oxidative stress, decreased L-arginine and tetrahydrobiopterin. This study tested the hypothesis that dietary cosupplementation with tetrahydrobiopterin (BH4), L-arginine, and vitamin C acts synergistically to decrease oxidative stress, increase nitric oxide and improve blood flow in response to acute hindlimb ischemia. Rats were fed normal chow, chow supplemented with BH4 or L-arginine (alone or in combination) or chow supplemented with BH4 + L-arginine + vitamin C for 1 wk before induction of unilateral hindlimb ischemia. Cosupplementation with BH4 + L-arginine resulted in greater eNOS expression, Ca²⁺-dependent NOS activity and NO concentration in gastrocnemius from the ischemic hindlimb, as well as greater recovery of foot perfusion and more collateral artery enlargement than did rats receiving either agent separately. The addition of vitamin C to the BH4 + L-arginine regimen did further increase these dependent variables, although only the increase in eNOS expression reached statistical significances. In addition, rats given all three supplements demonstrated significantly less Ca²⁺-independent activity, less nitrotyrosine accumulation, greater glutathione:glutathione disulfide (GSH:GSSG) ratio and less gastrocnemius muscle necrosis, on both macroscopic and microscopic levels. In conclusion, cosupplementation with BH4 + L-arginine + vitamin C significantly increased vascular perfusion after hindlimb ischemia by increasing eNOS activity and reducing oxidative stress and tissue necrosis. Oral cosupplementation of L-arginine, BH4 and vitamin C holds promise as a biological therapy to induce collateral artery enlargement.

Topics: Administration, Oral; Animals; Antioxidants; Arginine; Ascorbic Acid; Biopterins; Calcium; Drug Synergism; Enzyme Activation; Hindlimb; Ischemia; Male; Muscle, Skeletal; Necrosis; Nitric Oxide; Nitric Oxide Synthase Type III; Oxidative Stress; Rats; Rats, Sprague-Dawley; Regional Blood Flow

Therapeutic angiogenesis has emerged as an attractive approach for the management of peripheral arterial disease in diabetic patients. Oxidative stress generated and aggravated by prolonged hyperglycemia may interfere with and destroy the newly formed blood vessels. Angiogenic effect of simvastatin has been reported; however, its exact mechanism is yet to be evaluated. In addition, the exact role of antioxidant vitamins in diabetic peripheral arterial disease is still controversial. The present study was undertaken to investigate the therapeutic potential of simvastatin and antioxidant vitamins (E and C) and their combined effects on angiogenesis in diabetic hind-limb ischemia. Streptozotocin diabetic rats were treated for 6 weeks with simvastatin either alone or in combination with vitamin E or vitamin C. Parameters of angiogenesis, nitric oxide, heme oxygenase-1 (HO-1), and oxidative stress markers were evaluated. CD31 immunostaining revealed an increased capillary density in ischemic gastrocnemious tissue of diabetic rats treated with either simvastatin or its combination with vitamin C. This effect was accompanied by up-regulated plasma levels of HO-1, nitric oxide, vascular endothelial growth factor (VEGF) and its intra-muscular receptor type-2 (Flk-1). Tissue reduced glutathione and antioxidant enzymes activities were normalized in groups treated with antioxidant vitamins or their combination with simvastatin with concomitant blunting of lipid peroxidation. Vitamins E and C, through their antioxidant effects, evidently enhanced the angiogenic effect of simvastatin in ischemic diabetic muscle. Hence, the use of antioxidant vitamins combined with statins to induce therapeutic angiogenesis is a promising strategy in the management of diabetes-associated peripheral arterial disease.

Topics: Angiogenesis Inducing Agents; Animals; Antioxidants; Ascorbic Acid; Biomarkers; Capillaries; Diabetes Complications; Disease Models, Animal; Heme Oxygenase-1; Hindlimb; Ischemia; Male; Neovascularization, Physiologic; Nitric Oxide; Oxidative Stress; Rats; Rats, Wistar; Simvastatin; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2; Vitamin E; Vitamins

Tetrahydrobiopterin has been shown to efficiently abrogate ischemia reperfusion injury (IRI). However, it is unclear, whether its beneficial action relies on cofactor activity of one of the five known tetrahydrobiopterin-dependent reactions or on its antioxidative capacity. We therefore compared tetrahydrobiopterin with the pterin derivate tetrahydroneopterin (similar biochemical properties, but no nitric oxide synthase cofactor activity) and the antioxidants vitamin C and 5-methyltetrahydrofolate. Donor mice were pretreated with tetrahydrobiopterin, tetrahydroneopterin, vitamin C, or 5-methyltetrahydrofolate. Pancreatic grafts were subjected to 16-h cold ischemia time and implanted in syngeneic recipients. Untreated and nontransplanted animals served as controls. Following 2-h reperfusion, microcirculation was analyzed by intravital fluorescence microscopy. Graft damage was assessed by histology and nitrotyrosine immunostaining, and tetrahydrobiopterin levels were determined by HPLC. Recipient survival served as ultimate readout. Prolonged cold ischemia time resulted in microcirculatory breakdown. Only tetrahydrobiopterin pretreatment succeeded to preserve the capillary net, whereas all other compounds showed no beneficial effects. Along with increased intragraft tetrahydrobiopterin levels during recovery and implantation, only tetrahydrobiopterin pretreatment led to significant reduction of IRI-related parenchymal damage enabling recipient survival. These results show a striking superiority of tetrahydrobiopterin in preventing lethal IRI compared with related compounds and suggest nitric oxide synthases as treatment target.

Topics: Animals; Antioxidants; Ascorbic Acid; Biopterins; Cold Ischemia; Immunohistochemistry; Ischemia; Liver; Male; Mice; Mice, Inbred C57BL; Microcirculation; Microscopy, Confocal; Nitric Oxide; Organ Preservation; Pancreas; Pancreas Transplantation; Reperfusion Injury; Tetrahydrofolates; Time Factors

Nitric oxide (NO) derived from endothelial nitric oxide synthase (eNOS) is a potent vasodilator and signaling molecule that plays essential roles in neovascularization. During limb ischemia, decreased NO bioavailability occurs secondary to increased oxidant stress, decreased L-arginine and tetrahydrobiopterin. This study tested the hypothesis that dietary cosupplementation with tetrahydrobiopterin (BH4), L-arginine and vitamin C acts synergistically to decrease oxidant stress, increase NO and thereby increase blood flow recovery after hindlimb ischemia. Rats were fed normal chow, chow supplemented with BH4 or L-arginine (alone or in combination) or chow supplemented with BH4 + L-arginine + vitamin C for 1 wk before induction of hindlimb ischemia. In the is-chemic hindlimb, cosupplementation with BH4 + L-arginine resulted in greater eNOS and phospho-eNOS (P-eNOS) expression, Ca(2+)-dependent NOS activity and NO concentration in the ischemic calf region (gastrocnemius), as well as greater NO concentration in the region of collateral arteries (gracilis). Rats receiving cosupplementation of BH4 + L-arginine led to greater recovery of foot perfusion and greater collateral enlargement than did rats receiving either agent separately. The addition of vitamin C to the BH4 + L-arginine regimen further increased these dependent variables. In addition, rats given all three supplements showed significantly less Ca(2+)-independent activity, less nitrotyrosine accumulation, greater glutathione (GSH)-to-glutathione disulfide (GSSG) ratio and less gastrocnemius muscle necrosis, on both macroscopic and microscopic levels. In conclusion, co-supplementation with BH4 + L-arginine + vitamin C significantly increased blood flow recovery after hindlimb ischemia by reducing oxidant stress, increasing NO bioavailability, enlarging collateral arteries and reducing muscle necrosis. Oral cosupplementation of BH4, L-arginine and vitamin C holds promise as a biological therapy to induce collateral artery enlargement.

Topics: Administration, Oral; Animals; Arginine; Ascorbic Acid; Biopterins; Calcium; Drug Synergism; Hindlimb; Ischemia; Male; Models, Biological; Muscles; Nitrates; Nitric Oxide; Nitric Oxide Synthase Type III; Nitrites; Oxidative Stress; Phosphorylation; Rats; Rats, Sprague-Dawley; Recovery of Function; Regional Blood Flow

Peripheral arterial disease (PAD) is a major health problem especially when associated to concomitant diabetes and hypercholesterolemia. Hyperglycemia with an overwhelming generation of oxygen radicals and formation of glycation end-products exacerbates oxidation-sensitive mechanisms activated by tissue ischemia. Administration of autologous bone marrow cells (BMC) is an increasing notable intervention to induce therapeutic angiogenesis, ameliorated by metabolic intervention (MT). Recently, hemangioblasts (HS) with functional properties were isolated.. The effects of integrate regimen with intravenous BMC, HS, and MT (1.0% vitamin E, 0.05% vitamin C, and 6% l-arginine) were examined in the ischemic hindlimb of ApoE(-/-) diabetic and non-diabetic. Blood flow ratio was monitored by use of a laser Doppler blood flowmeter. Capillary density was determined in sections of the adductor and semimembranous muscles with antibody against CD31.. BMC or HS alone, and BMC plus HS increased blood flow and capillary densities and decreased interstitial fibrosis. These effects were amplified by additional MT, at least in part, through the nitric oxide pathway, reduction of systemic oxidative stress and macrophage infiltration. Investigation of molecular mechanisms in bone marrow (BM)-derived progenitor cells from mice revealed that BMC therapy and, more consistently, in combination with MT ameliorated functional activity via decreased cellular senescence and increased telomerase and chemokine CXCR4 activities. Telomerase activity was also increased by HS alone or HS+MT and, more consistently, by BMC+HS alone or in combination with MT.. Intravenous autologous BMC and HS intervention together with MT increased therapeutic angiogenesis in the ApoE(-/-) diabetic mouse hindlimb.

Topics: Animals; Apolipoproteins E; Arginine; Ascorbic Acid; Bone Marrow Transplantation; Diabetes Mellitus, Experimental; Hemangioblasts; Hindlimb; Ischemia; Mice; Neovascularization, Physiologic; Peripheral Vascular Diseases; Regional Blood Flow; Vitamin E

Rat liver was subjected to two-thirds warm ischemia for 45 min and reperfusion (I/R) to evaluate the resulting oxidative stress. The plasma alanine aminotransferase and aspartate aminotransferase activities were significantly higher than those in the sham group 1.5-24 h after I/R, showing extensive liver cell death. The level of oxidative stress was compared between the ischemic and non-ischemic regions based on the change in antioxidative vitamins C and E. The vitamin C level was significantly decreased during I/R in both the ischemic and non-ischemic regions 0, 1.5, 3, 6, 12, and 24 h after the start of reperfusion, showing enhanced oxidative stress even in the non-ischemic lobules. This decrease of vitamin C in the ischemic region was significantly higher than that in the non-ischemic lobules, while the vitamin E content was decreased only in the ischemic lobes, demonstrating higher oxidative stress in the ischemic region than that in the non-ischemic region. Early transient activation of cytoprotective extracellular signal-related kinase (ERK) was apparent in both the ischemic and non-ischemic lobules, reflecting oxidative stress in both regions. Early transient activation of c-Jun NH(2)-terminal kinase (JNK) was only apparent in the ischemic region, corresponding to extensive oxidative stress and liver cell death. These results demonstrate that significant oxidative stress was induced, but that JNK leading to cell death was not activated in the non-ischemic part of the liver.

Topics: Alanine Transaminase; Animals; Ascorbic Acid; Aspartate Aminotransferases; Ischemia; Liver; Male; Mitogen-Activated Protein Kinases; Oxidative Stress; Rats; Rats, Wistar; Reperfusion Injury; Vitamin E

Recent data demonstrated that hind limb ischemia induces skeletal muscle mitochondrial dysfunctions. Improvement of such metabolic myopathy improves patient's symptomatology, supporting the development of experimental models focused on mitochondrial function analysis. However, although the nonischemic contralateral leg is often used as a control during unilateral leg ischemia, whether it might be useful when assessing ischemia-induced mitochondrial dysfunction remains to be investigated.. Both ischemic (IR) and nonischemic contralateral legs (CTL) of rats (n=13) submitted to 5 h ischemia induced by a rubber band tourniquet applied on the root of the hind limb were studied and compared to that of sham-operated animals (SHAM, n=13). Maximal oxidative capacities (V(max)) and complexes I, II and IV activities of the gastrocnemius mitochondrial respiratory chain were determined, using glutamate-malate, succinate (Vs) and TMPD-ascorbate (V(TMPD)) substrates.. V(max) was decreased in IR (4.6+/-0.4 microM/min/g dry weight) compared to both SHAM and CTL muscles (8.5+/-0.5 and 7.1+/-0.4 microM/min/g dry weight, -46% and -36%, P<0.001, respectively). V(S) and V(TMPD) were reduced in IR muscle (-56% and -48% for V(S); and -25% and -24% for V(TMPD), P<0.001) as compared to SHAM and CTL). V(S) and V(TMPD) were similar in SHAM and CTL muscles.. Five hours ischemia-reperfusion significantly impaired complexes I, II and IV of the ischemic skeletal muscle mitochondrial respiratory chain. Interestingly, only V(max) was slightly altered in the contralateral leg, supporting that the nonischemic leg might be used as a control when assessing mitochondrial function in the experimental setting of unilateral hind limb ischemia.

Topics: Animals; Ascorbic Acid; Cell Respiration; Electron Transport Chain Complex Proteins; Glutamic Acid; Ischemia; Lower Extremity; Malates; Male; Mitochondria, Muscle; Mitochondrial Diseases; Muscle, Skeletal; Rats; Rats, Wistar; Reperfusion Injury; Succinic Acid; Tetramethylphenylenediamine

In exercise, as well as cancer and ischemia, hypoxia-inducible factor 1 (HIF1) transcriptionally activates hundreds of genes vital for cell homeostasis and angiogenesis. While potentially beneficial in ischemia, upregulation of the HIF1 transcription factor has been linked to inflammation, poor prognosis in many cancers, and decreased susceptibility of tumors to radiotherapy and chemotherapy. Considering HIF1's function, HIF1alpha protein and its hydroxylation cofactors look increasingly attractive as therapeutic targets. Independently, antioxidants have shown promise in lowering the risk of some cancers and improving neurological and cardiac function following ischemia. The mechanism of how different antioxidants and reactive oxygen species influence HIF1alpha expression has drawn interest and intense debate. Here we present an experimentally based computational model of HIF1alpha protein degradation that represents how reactive oxygen species and antioxidants likely affect the HIF1 pathway differentially in cancer and ischemia. We use the model to demonstrate effects on HIF1alpha expression from combined doses of five potential therapeutically targeted compounds (iron, ascorbate, hydrogen peroxide, 2-oxoglutarate, and succinate) influenced by cellular oxidation-reduction and involved in HIF1alpha hydroxylation. Results justify the hypothesis that reactive oxygen species work by two opposite ways on the HIF1 system. We also show how tumor cells and cells under ischemic conditions would differentially respond to reactive oxygen species via changes to HIF1alpha expression over the course of hours to days, dependent on extracellular hydrogen peroxide levels and largely independent of initial intracellular levels, during hypoxia.

Topics: Animals; Ascorbic Acid; Cell Hypoxia; Down-Regulation; Humans; Hydrogen Peroxide; Hypoxia-Inducible Factor 1, alpha Subunit; Iron; Ischemia; Jurkat Cells; Ketoglutaric Acids; Models, Biological; Neoplasms; Rats; Reactive Oxygen Species; Succinic Acid; Up-Regulation

We have previously shown oxidative stress and oedema, caused by both xanthine oxidase-derived oxidants and infiltrating neutrophils, within skeletal muscle after contractile-induced claudication. The purpose of this study was to determine whether supplementation with antioxidant vitamins attenuates the oxidative stress, neutrophil infiltration and oedema associated with an acute bout of contractile-induced claudication. Rats received vehicle, vitamin C, vitamin E or vitamin C + E for 5 days prior to contractile-induced claudication. Force production was significantly reduced in the claudicant limbs of all groups compared with the control (sham) limb of control animals. Contractile-induced claudication caused a significant increase in protein oxidation, lipid peroxidation, neutrophil infiltration and oedema compared with sham muscles. Supplementation with vitamin C, E or C + E prevented the increases in each of these, and there were no differences between groups. These findings suggest that, in an animal model of exercise-induced claudication, neutrophil chemotaxis is caused by oxidizing species and that antioxidant supplementation can prevent oxidative damage, neutrophil infiltration and oedema following an acute bout of contractile-induced claudication.

Topics: Animals; Antioxidants; Ascorbic Acid; Disease Models, Animal; Edema; Electric Stimulation; Intermittent Claudication; Ischemia; Lipid Peroxidation; Male; Muscle Contraction; Muscle, Skeletal; Neutrophil Infiltration; Neutrophils; Oxidative Stress; Peroxidase; Protein Carbonylation; Rats; Rats, Sprague-Dawley; Severity of Illness Index; Vitamin E

This study was designed to investigate the effects of peripheral arterial insufficiency, exercise, and vitamin C administration on muscle performance, cross-sectional area, and ultrastructural morphology in extensor digitorum longus (EDL) and soleus (Sol) muscles in rats. Adult Wistar rats were assigned to ischemia alone (isch), ischemia-exercised (exe), ischemia-vitamin C (vit C), and ischemia-exercise-vitamin C (vit C + exe) groups. Ischemia was achieved via unilateral ligation of the right common iliac artery. Contralateral muscles within the same animal served as controls. Exercise protocol consisted of 50-min intermittent level running performed every other day for 5 days. Vitamin C (100 mg/kg body wt) was administered intraperitoneally on a daily basis throughout the 14 days of the experiment. With regard to the EDL muscle, ischemia alone reduced muscle strength, which was not recovered after vitamin C administration. Exercise alone following ischemia induced the most severe structural damage and cross-sectional area decrease in the muscle, yet the reduction in tetanic tension was not significant. Exercise in conjunction with vitamin C administration preserved ischemia-induced EDL muscle tetanic tension. In the Sol muscle, a significant reduction in single twitch tension after vitamin C administration was found, whereas the tetanic force of the ischemic Sol was not significantly decreased compared with the contralateral muscles in any group. Ischemic Sol muscle cross-sectional area was reduced in all but the exe groups. In Sol, muscle strength was reduced in the vit C group, and mean cross-sectional area of ischemic Sol muscles was reduced in all groups except the exe group. These results illustrate that mild exercise, combined with a low dose of vitamin C supplementation, may have beneficial effects on ischemic EDL muscle with a smaller effect on the Sol muscle.

Topics: Animals; Antioxidants; Ascorbic Acid; Chronic Disease; Dietary Supplements; Dose-Response Relationship, Drug; Female; Ischemia; Male; Muscle, Skeletal; Physical Conditioning, Animal; Rats; Rats, Wistar

Reactive oxygen species (ROS) have been implicated in the cellular membrane damage and postoperative morbidity associated with obligatory ischemia-reperfusion (I-R) during vascular surgery. Thus, a clinical study was undertaken to evaluate the effects of ascorbate prophylaxis on ROS exchange kinetics in 22 patients scheduled for elective abdominal aortic aneurysm (AAA) or infra-inguinal bypass (IIB) repair. Patients were assigned double-blind to receive intravenous sodium ascorbate (2 g vitamin C, n=10) or placebo (0.9% saline, n=12) administered 2 h prior to surgery. Blood samples were obtained from the arterial and venous circulation proximal to the respective sites of surgical repair (local) and from an antecubital vein (peripheral) during cross-clamping (ischemia) and within 60 s of clamp release (reperfusion). Ascorbate supplementation increased the venoarterial concentration difference (v-adiff) of lipid hydroperoxides (LH), interleukin (IL)-6 and vascular endothelial growth factor (VEGF) protein during ischemia. This increased the peripheral concentration of LH, total creatine phosphokinase (CPK), and VEGF protein during reperfusion (P<0.05 vs placebo). Electron paramagnetic resonance (EPR) spectroscopy confirmed that free iron was available for oxidative catalysis in the local ischemic venous blood of supplemented patients. An increased concentration of the ascorbate radical (A.-) and alpha-phenyl-tert-butylnitrone (PBN) adducts assigned as lipid-derived alkoxyl (LO.) and alkyl (LC.) species were also detected in the peripheral blood of supplemented patients during reperfusion (P<0.05 vs ischemia). In conclusion, these findings suggest that ascorbate prophylaxis may have promoted iron-induced oxidative lipid damage via a Fenton-type reaction initiated during the ischemic phase of surgery. The subsequent release of LH into the systemic circulation may have catalyzed formation of second-generation radicals implicated in the regulation of vascular permeability and angiogenesis.

Topics: Aged; Aortic Aneurysm, Abdominal; Ascorbic Acid; Dietary Supplements; Double-Blind Method; Electron Spin Resonance Spectroscopy; Free Radical Scavengers; Humans; Interleukin-6; Iron; Ischemia; Lipid Peroxides; Oxidation-Reduction; Oxidative Stress; Prospective Studies; Reactive Oxygen Species; Reperfusion; Vascular Endothelial Growth Factor A

Oxidative stress seems to contribute to cardiopulmonary bypass (CPB)-related postoperative complications. Pediatric patients are particularly prone to these complications. With this in mind, we measured oxidative stress markers in blood plasma of 20 children undergoing elective heart surgery before, during, and up to 48 h after cessation of CPB, along with inflammatory parameters and full analysis of iron status. Ascorbate levels were decreased by approximately 50% (P < 0.001) at the time of aorta cross-clamp removal (or pump switch-off in 4 patients with partial CPB), and associated with corresponding increases in dehydroascorbate (P < 0.001, r = -0.80) and malondialdehyde (P < 0.01, r = -0.59). In contrast to the immediate oxidative response, peak levels of IL-6 and IL-8 were not observed until 3-12 h after CPB cessation. The early loss of ascorbate correlated with duration of CPB (P < 0.002, r = 0.72), plasma hemoglobin after cross-clamp removal (P < 0.001, r = 0.70), and IL-6 and IL-8 levels at 24 and 48 h after CPB (P < 0.01), but not with postoperative lactate levels, strongly suggesting that hemolysis, and not inflammation or ischemia, was the main cause of early oxidative stress. The correlation of ventilation time with early changes in ascorbate (P < 0.02, r = 0.55), plasma hemoglobin (P < 0.01, r = 0.60), and malondialdehyde (P < 0.02, r = 0.54) suggests that hemolysis-induced oxidative stress may be an underlying cause of CPB-associated pulmonary dysfunction. Optimization of surgical procedures or therapeutic intervention that minimize hemolysis (e.g., off-pump surgery) or the resultant oxidative stress (e.g., antioxidant treatment) should be considered as possible strategies to lower the rate of postoperative complications in pediatric CPB.

Topics: Ascorbic Acid; C-Reactive Protein; Cardiac Surgical Procedures; Cardiopulmonary Bypass; Child; Child, Preschool; Dehydroascorbic Acid; Heart Defects, Congenital; Hemolysis; Humans; Infant; Interleukin-6; Interleukin-8; Iron; Ischemia; Malondialdehyde; Neutrophils; Oxidative Stress; Pneumonia; Postoperative Complications; Prospective Studies

We have shown that acrolein, a lipid peroxidation byproduct, can inflict significant damage in isolated spinal cord white matter following oxygen glucose deprivation (OGD). The mechanism of such acrolein-induced damage is unclear. The aim of this study was to examine whether glutathione (GSH) and ascorbic acid, two reactive oxygen species (ROS) scavengers, can alleviate functional and anatomical damage due to acrolein.. We used an OGD injury model with isolated guinea pig spinal cord white matter. Sucrose gap recording was used to monitor axonal impulse conduction, and a horseradish peroxidase exclusion test was employed to determine membrane integrity. The functional and anatomical parameters were compared in three groups: acrolein, acrolein/GSH and acrolein/ascorbic acid.. We found that while GSH resulted in an 87% recovery of compound action potential conductance, ascorbic acid produced a 97% recovery, compared with a 69% recovery in an injured group without treatment. It is noted that GSH, and to a lesser extent ascorbic acid, preferentially enhanced functional recovery in smaller axons.. Acrolein-induced neuronal damage is likely mediated by ROS. Furthermore, GSH and ascorbic acid are effective in suppressing acrolein and free radical-induced injury in spinal cord white matter.

Topics: Acrolein; Action Potentials; Animals; Antioxidants; Ascorbic Acid; Axons; Female; Free Radical Scavengers; Glucose; Glutathione; Guinea Pigs; Histocytochemistry; Horseradish Peroxidase; Ischemia; Perfusion; Reperfusion Injury; Spinal Cord Ischemia

This study describes a novel analytical system integrating in vivo microdialysis sampling with a radial thin-layer flow cell with a single-walled carbon nanotube (SWNT)-modified glassy carbon electrode as working electrode for continuous and on-line monitoring of ascorbate depletion in the rat striatum induced by global ischemia. The SWNTs, especially those after vacuum heat treatment at 500 degrees C, are found to be able to enhance the electron-transfer kinetics of ascorbate oxidation at a low potential (ca. -50 mV) and possess a strong ability against electrode fouling. These properties essentially make it possible to determine ascorbate with a good stability and high selectivity against catecholamines and their metabolites and other electroactive species of physiological levels. While being integrated with in vivo microdialysis to assemble an on-line analytical system, the electrode is proved useful for continuous and sensitive monitoring of the basal dialysate level of ascorbate and its depletion in the rat striatum induced by global ischemia. The basal dialysate level of ascorbate is determined to be 5.0 +/- 0.5 microM (n = 5) and a 50 +/- 10% (n = 3) depletion is recorded for the basal ascorbate after 4 h of global ischemia.

Topics: Animals; Ascorbic Acid; Corpus Striatum; Electrochemistry; Electrodes; Free Radicals; Ischemia; Male; Molecular Structure; Nanotubes, Carbon; Online Systems; Oxidation-Reduction; Rats; Rats, Sprague-Dawley; Reproducibility of Results

The aim of this study was to ascertain the possibility of diminishing ischemia-reperfusion injury by intravenous application of the chosen antioxidants: vitamin C, mannitol, and N-acetylcysteine.. The study was performed on New Zealand Red male rabbits, which were divided into 6 groups of 8. In group 1, 5 segments of the small intestine were taken for histopathologic examination (normal intestine). In group 2, segments of the small intestine were taken for histopathologic examination after 3 hours of closure of the superior mesenteric artery (ischemic intestine). In group 3, after 3 hours of closure of the superior mesenteric artery, 1 hour of reperfusion took place. In this group, blood flow in the superior mesenteric artery was measured within the first 30 minutes, and segments of the small intestine were taken for histopathologic examination after 60 minutes of the reperfusion. In groups 4, 5, and 6 the procedure was similar to that in group 3, but additionally the rabbits were given antioxidants intravenously: in group 4, vitamin C, 250 mg/kg; in group 5, 20% mannitol, 3 mL/kg; and in group 6, N-acetylcysteine, 100 mg/kg.. All the chosen antioxidants had a beneficial influence on the blood flow in the superior mesenteric artery. The blood flow in the groups with antioxidants after 30 minutes of the reperfusion was 53% to 57% of initial values compared with 27% of initial values in group 3. In histopathologic evaluation, protective action of the antioxidants was seen in the groups with vitamin C and mannitol.. Application of the chosen antioxidants reduces injury of the rabbit small intestine caused by reperfusion after 3 hours of closure of the superior mesenteric artery.

Topics: Acetylcysteine; Animals; Antioxidants; Ascorbic Acid; Edema; Hemorrhage; Intestinal Mucosa; Intestine, Small; Ischemia; Ligation; Male; Mannitol; Mesenteric Artery, Superior; Oxidative Stress; Rabbits; Reperfusion Injury

To estimate ischemic tissue damage in ovarian cortex and to evaluate the effectiveness of ascorbic acid, an antioxidant, to protect ovarian tissue from apoptosis caused by ischemia.. In vitro laboratory experiments.. Academic research institute.. Fresh and frozen/thawed cortical sections of bovine ovaries were incubated in MEM medium with or without ascorbic acid for a duration of 3, 24, and 48 hours at 37 degrees C.. Oxygen consumption rates, lactate dehydrogenase concentrations, apoptosis rates determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining, and DNA fragmentation analysis.. The oxygen consumption rates were correlated inversely with the duration of incubation. When the rates of apoptosis in primordial follicles with or without ascorbic acid treatment were compared, there was no statistically significant difference between the two groups. However, the ascorbic acid treatment group showed significantly decreased apoptosis in ovarian cortex (stromal cells) with 24 hours of incubation.. The correlation between ischemic tissue damage and the duration of ischemia was verified. Ovarian cortex could tolerate ischemia at least for 3 hours. Ascorbic acid treatment reduced apoptosis in ovarian cortex up to 24 hours of incubation in vitro. It appeared that stromal cells were more vulnerable to ischemia compared to primordial follicles.

Topics: Animals; Antioxidants; Apoptosis; Ascorbic Acid; Cattle; Disease Models, Animal; Female; Ischemia; Ovary; Oxygen Consumption

The major damaging factor during and after the ischemic/hypoxic insult is the generation of free radicals, which leads to apoptosis, necrosis, and ultimately cell death. Rubia cordifolia (RC), Fagonia cretica linn (FC), and Tinospora cordifolia (TC) have been reported to contain a wide variety of antioxidants and have been in use in the eastern system of medicine for various disorders. Hippocampal slices were subjected to oxygen-glucose deprivation (OGD) and divided into three groups, control, OGD, and OGD+drug treated. Cytosolic reduced glutathione (GSH), nitric oxide [NO, measured as nitrite (NO2)]. EPR was used to establish the antioxidant effect of RC, FC, and TC with respect to superoxide anion (O*2-), hydroxyl radicals (*OH), nitric oxide (NO) radical, and peroxynitrite anion (ONOO-) generated from pyrogallol, menadione, DETA-NO, and Sin-1, respectively. RT-PCR was performed for the three herbs to assess their effect on the expression of gamma-glutamylcysteine ligase (GCLC), iNOS, and GAPDH gene expression. All the three herbs were effective in elevating the GSH levels and expression of the GCLC. The herbs also exhibited strong free radical scavenging properties against reactive oxygen and nitrogen species as revealed by electron paramagnetic resonance spectroscopy, diminishing the expression of iNOS gene. RC, FC, and TC therefore attenuate oxidative stress mediated cell injury during OGD and exert the above effects at both the cytosolic as well as at gene expression levels and may be effective therapeutic tool against ischemic brain damage.

Topics: Animals; Ascorbic Acid; Electrodes; Electron Spin Resonance Spectroscopy; Electrons; Free Radical Scavengers; Free Radicals; Glucose; Glutamate-Cysteine Ligase; Glutathione; Hippocampus; Hypoxia; Ions; Ischemia; Lipid Peroxidation; Male; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Oxygen; Plant Extracts; Rats; Rats, Wistar; Reactive Nitrogen Species; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Rubia; Time Factors; Tinospora; Zygophyllaceae

To investigate whether combined pretreatment with lipid- and water-soluble antioxidants gave better restoration of energy phosphates after ischaemia-reperfusion of rabbit kidneys than single pretreatment with a lipid-soluble antioxidant.. Thirteen New Zealand white rabbits were used for the study. Changes in energy phosphates were measured in vivo using volume-selective 31P magnetic resonance spectroscopy. The indeno-indole compound H290/51 was chosen as a lipid-soluble antioxidant and ascorbate as a water-soluble antioxidant.. The combined pretreatment led to significantly better restoration of the beta-adenosine triphosphate:inorganic phosphate ratio after 60 min of ischaemia and 120 min of reperfusion compared with the single pretreatment. Analyses of blood pressure and blood gas changes showed that the beneficial effect of combined pretreatment was not caused by a better general condition of the animals in that group but by a direct effect on the kidneys.. Combined pretreatment with lipid- and water-soluble antioxidants leads to better restoration of energy phosphates in rabbit kidneys subjected to ischaemia-reperfusion compared with single pretreatment with a lipid-soluble antioxidant.

Topics: Analysis of Variance; Animals; Antioxidants; Ascorbic Acid; Disease Models, Animal; Female; Indoles; Ischemia; Kidney Diseases; Kidney Function Tests; Lipid Peroxidation; Magnetic Resonance Spectroscopy; Male; Monitoring, Physiologic; Phosphorus Isotopes; Probability; Rabbits; Random Allocation; Reperfusion Injury; Sensitivity and Specificity; Solubility

The objectives of this study were to compare the protective influence of exogenous nitric oxide on renal ischemia reperfusion (I/R) injury with that of the antioxidant vitamins C and E. Sprague-Dawley rats were divided into three groups ( n=12 per group). Normal saline solution was given in group 1, a vitamin C (200 mg/kg/d) plus vitamin E (100 mg/kg/d) combination in group 2 for 3 days before operating and Na-nitroprusside (5 mg/kg/d) in group 3 before reperfusion. The left kidneys were exposed to warm ischemia for 40 min followed by reperfusion for 90 min. The right kidneys were used as internal controls. After both kidneys were removed, histopathological examinations were performed, and oxidative and antioxidative parameters were measured. In the postischemic reperfused rat kidneys, the renal lipid peroxidation level was significantly lower, and the renal GSH level higher in the group given Na-nitroprusside compared with groups 1 and 2. Renal specific xanthine oxidase activity was also significantly lower in the group treated with Na-nitroprusside than in the groups given vitamins or saline. There was a significant, negative correlation between lipid peroxidation and reduced glutathione levels. Our results suggest that the exogenous nitric oxide (Na-nitroprusside) inhibits xanthine oxidase, and has more apparent preventive features for renal I/R injury than the antioxidant vitamins C+E.

Topics: Animals; Antioxidants; Ascorbic Acid; Glutathione; Ischemia; Kidney; Lipid Peroxides; Male; Nitric Oxide; Rats; Rats, Sprague-Dawley; Reference Values; Renal Circulation; Reperfusion Injury; Vitamin E; Xanthine Oxidase

Recirculation after transient intrauterine ischemia has previously been found to be accompanied by secondary mitochondrial dysfunction in the immature rat brain. This study was performed to assess the efficacy of combined treatment with ascorbic acid and alpha-tocopherol in improving secondary brain damage. On the 17th day of gestation, transient intrauterine ischemia was induced by 30 minutes of uterine artery occlusion. Either vehicle, ascorbic acid, alpha-tocopherol, or combination of ascorbic acid and alpha-tocopherol was randomly administered to pregnant rats before and after occlusion. The pups were delivered by cesarean section at 21 days of gestation, and cerebral neocortical tissue was sampled. The mitochondrial respiration was measured polarographically in homogenates. In the ischemia uterine horn, mitochondrial activity of the vehicle treatment decreased significantly to 56% of nonischemic controls. Treatment with ascorbic acid or alpha-tocopherol alone demonstrated a moderate improvement of the secondary mitochondrial dysfunction to 64% and 62% of nonischemic controls, respectively. The combined treatment caused a normalization of mitochondrial activity to 91% of nonischemic controls. These results indicate that combined treatment with ascorbic acid and alpha-tocopherol has a more protective effect against secondary mitochondrial dysfunction after transient intrauterine ischemia compared with the administration of ascorbic acid or alpha-tocopherol alone.

Topics: alpha-Tocopherol; Animals; Animals, Newborn; Antioxidants; Ascorbic Acid; Brain; Female; Fetal Diseases; Ischemia; Mitochondria; Mitochondrial Diseases; Pregnancy; Rats; Rats, Wistar

In this prospective controlled study, the aim was to examine the effects of vitamin C, mannitol and verapamil on adnexial ischaemia-reperfusion injury in the rat ovary.. Thirty-six female Wistar rats were used. In the controls (group 1), only laparotomy was performed. In group 2, ovarian ischaemia was produced and the bilateral ovaries were surgically removed 4 h later. In group 3, an ischaemic period of 4 h was followed by reperfusion for 1 h; the bilateral ovaries were then removed. In groups 4, 5 and 6, after 4 h of ischaemia, either vitamin C, mannitol or verapamil respectively was infused before reperfusion; after 1 h of reperfusion the ovaries were removed. Thiobarbituric acid reactive substance (TBARS) levels were measured in all ovary tissues.. TBARS levels of the reperfusion group were significantly higher than those of groups treated with vitamin C or mannitol (P = 0.013 and P = 0.045 respectively), but not of the verapamil group.. Vitamin C and mannitol were found to be effective in reducing ischaemia-reperfusion injury of the ovary during its early stages, but verapamil was ineffective.

Topics: Animals; Antioxidants; Ascorbic Acid; Calcium Channel Blockers; Female; Free Radical Scavengers; Ischemia; Mannitol; Ovary; Rats; Rats, Wistar; Reperfusion Injury; Thiobarbituric Acid Reactive Substances; Verapamil

Reperfusion injury is considered primarily an inflammatory response to oxidative stress. In vitro, oxygen free radicals induce the formation of oxidized phospholipids with platelet-activating factor (PAF) activity (PAF-like lipids). We examined the following: 1) whether PAF and PAF-like lipids are released during reperfusion; 2) the relationship between these phospholipids and oxidative damage on the one hand, and leukocyte recruitment in renal tissue on the other; and 3) whether antioxidant treatment influences the behavior of these phospholipids, the renal inflammatory response, and the outcome of postischemic acute renal failure. After 60 min of warm renal ischemia in rabbits, a release of PAF and, particularly, PAF-like lipids was seen in the first 15 min of reperfusion. In addition, the release of those phospholipids was associated with intense tissue DNA oxidation and with an increase in myeloperoxidase activity. Vitamin C was able to attenuate these postischemic oxidative changes, decrease PAF and PAF-like lipid levels, and, consequently, reduce myeloperoxidase activity. After 40 min of warm renal ischemia in rats, vitamin C treatment ameliorated renal function and structure. This is the first in vivo demonstration of the release of phospholipid oxidation products as part of an oxidative-inflammatory response after renal ischemia-reperfusion, with the release of phospholipid oxidation products significantly reduced by antioxidant treatment.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Ascorbic Acid; Creatinine; Deoxyguanosine; DNA Damage; Inflammation; Ischemia; Kidney; Lipoproteins, LDL; Oxidative Stress; Platelet Activating Factor; Rabbits; Rats

Fatty livers in humans and rats are less tolerant of ischemia, endotoxin, and alcohol. We hypothesized that fatty livers of obese (Ob) Zucker rats are oxidatively stressed and oxidative stress could be relieved by antioxidant treatment, leading to improved tolerance to ischemia. Total glutathione (GSH), tocopherol (TOC), ascorbic acid (AA), catalase (CAT), superoxide dismutase (SOD), and selenium-glutathione peroxidase (Se-GPx) were measured in the livers of Ob and lean (Ln) Zucker rats before and after treatment with high-dose TOC and ascorbate. Also, survival in treated Ob rats following a lethal 90 minutes of partial in vivo warm ischemia was examined. Fatty livers of Ob rats contained significantly less GSH, TOC, and CAT, in comparison with livers of Ln rats. Immunoblotting showed significantly decreased CAT protein without changes in mRNA in fatty livers. There were no significant differences in AA, SOD, and Se-GPx between the 2 groups. Pretreatment with TOC and ascorbate over 48 hours completely corrected the decreases in GSH, TOC, and CAT. Most importantly, TOC with or without ascorbate pretreatment significantly improved survival in Ob rats following ischemia in a dose-dependent manner. In conclusion, TOC administration corrected the oxidative stress in fatty livers of Ob Zucker rats and improved survival following lethal ischemia. Additional studies are needed to determine the efficacy of TOC-a relatively inexpensive agent-in treating patients with fatty livers in a variety of clinical conditions, possibly including liver transplantation.

Topics: Animals; Antioxidants; Ascorbic Acid; Catalase; Fatty Liver; Glutathione; Glutathione Peroxidase; Hot Temperature; Ischemia; Liver; Male; Obesity; Oxidative Stress; Rats; Rats, Zucker; Superoxide Dismutase; Vitamin E

Peroral administration of 70 mg/kg ascovertin and 150 mg/kg Leuzea extract to rats with cerebral ischemia for 5 days prevented destructive changes and decrease in the density of synapses in the cerebral cortex. These preparations activated compensatory and reparative mechanisms underlying plasticity of the synaptic pool, which was realized through hypertrophy and destruction of synaptic contacts. Ascovertin possessed more pronounced cerebroprotective activity than Leuzea extract.

Topics: Animals; Ascorbic Acid; Brain; Cerebral Cortex; Drug Combinations; Female; Hypertrophy; Ischemia; Male; Plant Extracts; Quercetin; Rats; Rats, Wistar; Synapses

Previous studies in isolated, ventilated lungs have demonstrated by indirect measurements that oxidant generation occurs during pulmonary ischemia before reperfusion. To identify and quantify the types of free radical species generated during ischemia, we used electron paramagnetic resonance (EPR) spectroscopy in the presence and absence of the spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). EPR spectra obtained from the vascular effluent of isolated ferret lungs, contained a doublet signal (g = 2.005) indicative of ascorbyl radical. This signal doubled in magnitude after 180 min of ischemia, providing evidence of oxidant formation during ischemia. When DMPO, which reacts with radicals including superoxide anions and hydroxyl radicals, was added to the perfusate, the spectra contained ascorbyl radical signals but no DMPO-adducts. To clarify the relationship between ascorbyl radical and DMPO-adduct formation, additional studies were conducted in the presence and absence of ascorbate with isolated lung mitochondria as the source of free radicals. The results showed that in the presence of ascorbate, oxygen free radicals were not detected by EPR spin trapping with DMPO because of the formation of prominent ascorbyl radical signals. These data suggest that DMPO may be useful for the detection of reactive oxygen species in isolated lungs, provided the ascorbate can be sufficiently depleted. Alternatively, as shown by our results, EPR studies that directly monitor ascorbyl radical formation may be used as a marker of oxidative stress in the lung.

Topics: Animals; Ascorbic Acid; Ferrets; Free Radicals; Ischemia; Lung; Magnetic Resonance Spectroscopy; Male; Mitochondria; Oxidative Stress; Reactive Oxygen Species

This study was conducted to (a) assess postischemic vasodilatation by changes in the vascular cross-sectional area using simultaneous intravascular two-dimensional and Doppler ultrasound before and after the infusion of Intralipid (Pharmacia & Upjohn, Peapack, NJ, U.S.A.); (b) evaluate how antioxidant ascorbic acid modifies the effects of Intralipid on postischemic vasodilatation: and (c) clarify the changes in plasma nitrite and nitrate (NOx-) levels after the infusion of Intralipid with and without ascorbic acid. Twenty-eight mongrel dogs were used to measure for vascular cross-sectional area and average instantaneous peak velocity in the iliac arteries after the 5-min occlusion of the arteries. Postischemic vasodilatation was impaired after the infusion of Intralipid (20%, 2 ml/kg) and this impaired response was reversed by the co-administration of ascorbic acid (30 mg/kg). NG-monomethyl-L-arginine completely abolished postischemic vasodilatation. Plasma NOx levels were significantly reduced after the infusion of Intralipid compared with baseline (11.6+/-0.4 vs. 12.9+/-0.3 microM, p = 0.025) and after infusion of Intralipid with ascorbic acid compared with baseline (11.8+/-0.5 vs. 13.1+/-0.4 microM, p = 0.047). We concluded that ascorbic acid reverses the endothelial dysfunction induced by Intralipid without increasing plasma NOx- levels and that deactivation of nitric oxide by oxidative stress is a primary contributor to Intralipid-induced impaired vasodilation.

Topics: Animals; Ascorbic Acid; Cholesterol; Coronary Circulation; Dogs; Enzyme Inhibitors; Fat Emulsions, Intravenous; Female; Iliac Artery; Infusions, Intravenous; Ischemia; Male; Nitrates; Nitric Oxide Synthase; Nitric Oxide Synthase Type III; Nitrites; omega-N-Methylarginine; Soybean Oil; Triglycerides; Vasodilation

Antioxidants are known to play an important role in mitigating oxidative stress injury. Regional concentrations of non-enzymatic antioxidants, redox ratio and lipid peroxides were studied in normal, ischemic and ischemic-reperfused rat hearts. Isolated perfused rat hearts were made globally ischemic for 45 min and reperfused for 15 min. Right ventricular wall (RVW), septum (S) and left ventricular wall (LVW) from control, ischemic (I) and reperfused (I-R) hearts were analysed. Tocopherol, retinol and ascorbic acid concentrations in different regions of perfused control hearts were not different. Reduced glutathione (GSH) was significantly lower in the RVW, while S and LVW had about three-fold higher levels. Oxidized glutathione (GSSG) was lower in the RVW and most concentrated in the LVW. The GSH:GSSG ratio was highest in the septum while RVW and LVW had similar values. Lipid hydroperoxide (LPx) concentrations in the three regions of control hearts were not different from each other. In I and I-R hearts, vitamin E declined in all three regions but the loss was significant only in the septum in the I group and in the septum and LVW of the I-R group. Vitamin A showed significant loss in all three regions of the I-R group. Vitamin C declined significantly only in the RVW of the I-R group. GSH increased in the RVW of the I and I-R groups compared to controls. GSSG was increased in the RVW and septum of the I group and in all regions of the I-R group. The redox ratio, GSH:GSSG, decreased in all regions of both I and I-R groups. LPx were increased in the septum of the I group and in all regions of the I-R group. Despite unique regional differences in non-enzymatic antioxidants, a comparable increase in LPx in the I-R group and similar extent of reduction in the redox ratio in different regions of the I and I-R groups, suggest that each myocardial region may use different antioxidant mechanisms to withstand oxidative stress.

Topics: Animals; Antioxidants; Ascorbic Acid; Glutathione; Glutathione Disulfide; Heart; Hypoxia; Ischemia; Lipid Peroxides; Male; Oxidative Stress; Perfusion; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Tissue Distribution; Vitamin A; Vitamin E

EPC-K1, a phosphate diester of alpha-tocopherol and ascorbic acid, is a new hydroxyl radical scavenger. We examined the effects of EPC-K1 according to differences in the timing of its administration. Warm ischemia, produced by vascular pedicle clamping, was sustained for 4 hours. After 24 hours of reperfusion, muscle injury was evaluated in 4 groups: the first group received a sham operation, the second group was treated with an intravenous injection of EPC-K1 prior to ischemia, the third group was treated with EPC-K1 prior to reperfusion, and the fourth group was controls. Compared with the control group, both the preischemic and pre-reperfusion EPC-K1-treated groups showed a statistically significant amelioration in the reduction of isometric muscle contraction. There were also significant reductions in the muscle and serum levels of thiobarbituric acid reactive substances (TBA-RS) and muscle damage, indicated by the biochemical and histological study. A comparison of the timing of EPC-K1 administration revealed that only the muscle TBA-RS level in the pre-reperfusion EPC-K1-treated group was significantly higher than that in the preischemic EPC-K1-treated group. These observations indicate that EPC-K1 not only by preischemic but also by pre-reperfusion administration acted effectively on reperfusion injury in muscle, thereby improving muscle function.

Topics: Animals; Antioxidants; Ascorbic Acid; Biopsy; Disease Models, Animal; Drug Administration Schedule; Drug Evaluation, Preclinical; Free Radical Scavengers; Injections, Intravenous; Ischemia; Isometric Contraction; Male; Muscle, Skeletal; Random Allocation; Rats; Rats, Inbred Lew; Reperfusion Injury; Thiobarbituric Acid Reactive Substances; Time Factors; Vitamin E

Cardiac arrhythmias during ischemia/reperfusion are believed to be related to free radicals generated in the heart especially during the period of reperfusion. Since melatonin functions as a free radical scavenger and antioxidant, the ability of this molecule to influence cardiac arrhythmias was investigated. The pineal secretory product, melatonin, reduced the incidence and severity of arrhythmias induced by ischemia/reperfusion due to ligation of the anterior descending coronary artery in the isolated rat heart. Melatonin was either infused during both the ischemia and reperfusion periods or only late in the ischemia period and throughout reperfusion. The percentage of hearts that developed cardiac arrhythmias during reperfusion as indicated by the incidence of premature ventricular contraction (PVC) and ventricular fibrillation (VF) were recorded. Melatonin either infused during both the ischemia and reperfusion periods or during essentially the period of reperfusion greatly reduced PVC and VF due to occlusion and reopening the anterior descending coronary artery. Presumably melatonin's beneficial effect in reducing cardiac arrhythmias was due in part to its free radical scavenging activity, which is greatly assisted by the rapidity with which it is taken up into cells. Previous studies have shown that vitamin C is effective in reducing the severity of cardiac arrhythmias induced by ischemia/reperfusion; thus, we also compared the efficacy of melatonin with this well-known antioxidant. Melatonin was more potent than vitamin C in protecting against arrhythmias induced by ischemia/reperfusion. Besides melatonin's function as a broad spectrum free radical scavenger, melatonin may have also reduced cardiac arrhythmias due to its regulation of intracellular calcium levels, i.e., by preventing calcium overloading, or due to its ability to suppress sympathetic nerve function and reduce adrenergic receptor function in the myocardium. Additional studies into the mechanisms of melatonin's action in reducing cardiac arrhythmias due to ischemia/reperfusion or other causes are warranted because of the possible application of this information to humans with heart disease.

Topics: Animals; Antioxidants; Arrhythmias, Cardiac; Ascorbic Acid; Dose-Response Relationship, Drug; Free Radical Scavengers; Heart; Ischemia; Male; Melatonin; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion; Reperfusion Injury

A number of antioxidants are present in human tissues, which comprise the secondary defence system against the oxygen-free radicals and oxidative stress. Therefore, this study was undertaken in an animal model to investigate the effects of antioxidants such as vitamin E, vitamin C, methyl prednisolone, and mannitol, on the treatment of intestinal reperfusion injury when given during ischemia.. The study was performed on six groups of animals, each composed of six rabbits: Group I, mesenteric ischemia group; group R, ischemia-reperfusion group; group E, ischemia-reperfusion plus Vitamin E treatment; group C, ischemia-reperfusion plus vitamin C treatment; group CS, ischemia-reperfusion plus corticosteroid treatment; and Group M, ischemia-reperfusion plus mannitol treatment. Malondialdehyde (MDA) and glutathione (GSH) levels of the intestinal mucosa were assayed to reflect the free radical formation.. Mucosal injury scores in the M and C groups were significantly lower than the R group (P< .01 and P< .01, respectively), and in the E and CS groups, mucosal injury scores were not significantly different from R group. MDA levels in the M and C groups were significantly lower than the R group (P < .01 and P < .01, respectively). GSH levels in the E, C, and M groups, were significantly higher than R group (P < .01, P < .05, and P < .01, respectively).. The results of this study showed that antioxidant drugs, such as vitamin C and mannitol, may play a role in attenuating reperfusion injury of the gut demonstrated by depression of tissue MDA levels and by elevation of tissue GSH levels.

Topics: Animals; Antioxidants; Ascorbic Acid; Disease Models, Animal; Glucocorticoids; Glutathione; Intestinal Mucosa; Intestines; Ischemia; Malondialdehyde; Mannitol; Methylprednisolone; Rabbits; Reperfusion Injury; Vitamin E

The effects of vitamin E on lipid peroxidation, intracellular free Ca2+ concentration ([Ca2+]i), and cell death were investigated in the postischemic immature cerebellum. Deprivation of oxygen and glucose for 10-min in a suspension of freshly dissociated granule cells from the cerebellum of 9-day-old male rat pups resulted in a recovery-induced consumption of cell nonenzymatic antioxidants (ascorbic acid, glutathione, and alpha-tocopherol) and development of membrane lipid peroxidation as measured by the thiobarbituric acid method. The rate of lipid peroxidation of the postischemic cells was stimulated, not reduced, by treatment of the cells with vitamin E (5-30 microM alpha-tocopherol phosphate). In flow-cytometric studies a 10-min period of ischemia resulted in a small increase in intracellular calcium concentration, lipid peroxidation products and cell death, but in the presence of alpha-tocopherol the same treatment caused a dramatic increase in cell death, accompanied by a large increase in [Ca2+]i and lipid peroxidation products. Pretreatment of the cells with a mixture of three antioxidants (vitamin C/rutin/ubiquinol-10, 10/5/1) or nickel (Ni2+) reduced the alpha-tocopherol-induced increases in [Ca2+]i, and cell death. Hydrogen peroxide (1 mM) and the water-soluble analogue of vitamin E, trolox (50 microM), mimicked the effect of vitamin E on lipid peroxidation in the postischemic cells. Pretreatment of the cells with the intracellular Ca2+ chelator BAPTA-AM, reduced both the alpha-tocopherol-induced increase in [Ca2+]i and cell death. The effect of vitamin E on [Ca2+]i was age dependent and decreased abruptly during maturation of the cerebellum between the first and second weeks of life. Results of in vitro treatment of the immature cerebellar cells with the water-soluble form of vitamin E (alpha-tocopherol phosphate) suggest that, after consumption of cellular co-antioxidants, vitamin E may be converted to an alpha-tocopheroxyl radical, which act as a toxic prooxidant as cellular bioenergetics deteriorate.

Topics: Animals; Antioxidants; Ascorbic Acid; Calcium; Cell Death; Cerebellum; Drug Synergism; Glutathione; Hydrogen Peroxide; Ischemia; Lipid Peroxidation; Male; Membrane Lipids; Rats; Rats, Wistar; Thiobarbituric Acid Reactive Substances; Vitamin E

Method of complex surgical treatment of inguinal hernia in children, basing on the early conduction of surgical correction of pathology, application of microsurgical technique of the operation conduction, using of pharmacologic defense of hematotesticular barrier and medicinal therapy of the man sexual gland ischemia, was elaborated and substantiated.

Topics: Age Factors; Antioxidants; Ascorbic Acid; Aspirin; Blood-Testis Barrier; Child; Dipyridamole; Hernia, Inguinal; Humans; Hyperbaric Oxygenation; Infant; Infant, Newborn; Inosine Diphosphate; Ischemia; Male; Microcirculation; Platelet Aggregation Inhibitors; Postoperative Care; Testis; Vasodilator Agents

The effect of intravenously administered ascorbate on the ischemic and reperfused rat skeletal muscle was investigated. Purine nucleotides and phospholipids in skeletal muscle from rats subjected to 4 h of ischemia followed by 1-h reperfusion were analyzed by high-performance liquid chromatography. In addition, ATP, phosphocreatine (PCr), Pi, and phosphomonoesters (PME) were analyzed by 31P-nuclear magnetic resonance at 202.4 MHz, and individual PME such as glucose-6-phosphate and IMP were quantified. PCr and ATP were exhausted after 4 h of ischemia and recovered poorly upon reperfusion in the soleus and tibialis muscle of untreated rats. Postischemic reperfusion resulted in significant loss of cardiolipin. Treatment with 55 mM ascorbate resulted in total restoration of PCr during reperfusion, and ATP recovered to 42% of control in the soleus. Recovery was improved in the tibialis as well, and the cardiolipin decrease was limited. A lower ascorbate concentration (5 mM) did not enhance postischemic recovery. Our findings show that a high dose of ascorbate improves the energetic state of rat skeletal muscle during postischemic reperfusion, probably due to its antioxidant function.

Topics: Animals; Ascorbic Acid; Cardiolipins; Cattle; Chromatography, High Pressure Liquid; Energy Metabolism; Female; Ischemia; Magnetic Resonance Spectroscopy; Muscle, Skeletal; Phosphates; Phosphatidylethanolamines; Phospholipids; Purine Nucleotides; Rats; Rats, Sprague-Dawley; Reperfusion

Ischemia-reperfusion injury by free radicals and lipid peroxides is observed in various organs. Ascorbic acid (AsA) or glutathione (GSH) in various doses (AsA:2, 0.5, 0.1 mmol/kg, GSH:2 mmol/kg) was intraperitoneally administered to male Wistar rats. The entire small intestines were resected just before ischemia, after ischemia, and after 20 min of reperfusion (n = 7-10 at each time point). At each time point, the specimens were subjected to assays of lipid peroxides, GSH, and glutaminase activity of the tissues; they were also examined histologically. In the AsA group, the production of lipid peroxides after reperfusion was significantly suppressed in a dose-dependent manner, and the ratio of oxidized GSH to total GSH was also significantly low. Tissue glutaminase activity decreased to a lesser extent, and the degree of injury was apparently less marked in the AsA group. This study indicates that AsA acts as an antioxidant against peroxidative tissue injury, possibly by scavenging radicals, preserving reduced GSH, and reducing the peroxidative reaction.

Topics: Animals; Ascorbic Acid; Dehydroascorbic Acid; Free Radicals; Glutathione; Glutathione Disulfide; Intestinal Mucosa; Intestine, Small; Ischemia; Lipid Peroxidation; Male; Mesenteric Arteries; Rats; Rats, Wistar; Reperfusion Injury; Thiobarbituric Acid Reactive Substances

Accumulation of products of lipid peroxidation (malondialdehyde, conjugated dienes, lipid peroxides, and Schiff bases) was evaluated in rabbit kidney cortex slices made ischemic for 60 min followed by 18 h storage at 5 degrees C in UW Na gluconate solution and 210 min normothermic reoxygenated incubation. In addition, the effect of adding Trolox (1 mM), deferoxamine (1 mM), and ascorbate (1 mM) as supplemental antioxidants to the UW gluconate solution was evaluated. Lipid peroxidation was slightly increased after hypothermic storage compared to slices subjected to ischemia alone but was not significantly different than ischemic slices during subsequent incubation at normothermia. The addition of either deferoxamine or Trolox to the storage solution substantially reduced lipid peroxidation both during hypothermic storage and subsequent to normothermic incubation. Ascorbate had a mild prooxidant effect as a sole additive to the UW gluconate solution but was clearly prooxidant when combined with either deferoxamine or Trolox. These results suggest that supplemental antioxidants added to the UW gluconate solution under conditions analogous to machine perfusion preservation have a potential role in reducing oxidative stress in kidney tissues harvested after warm ischemia and that hypothermia may be a valuable adjunct to resuscitative therapeutic regimens developed for salvage of ischemic kidneys for transplantation.

Topics: Animals; Antioxidants; Ascorbic Acid; Chromans; Cryopreservation; Deferoxamine; Ischemia; Kidney Cortex; Malondialdehyde; Rabbits; Tissue Preservation

Pharmacological experiments have suggested that ocular ischemia, induced by high intraocular pressure in the rabbit, provokes an oxidative stress responsible for functional alteration of the retina. However, the nature of the oxidant chemical species and their mode of generation were not elucidated. The aim of the present studies was to characterize the oxygen-derived free radicals produced during and/or after the hyperpressure period. The technique used was based on electron spin resonance spin trapping analysis of the signals obtained in microdialysates of the retina perfused with the nitrone 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO). The oxidative stress was also evaluated under ischemia and reperfusion periods by measuring the level of ascorbate in the retina via electron spin resonance detection of the ascorbyl free radical-dimethyl sulfoxide (AFR-DMSO) complex. Electroretinograms were recorded to determine the functional consequences of high intraocular pressure and free radical generation. Our results show that superoxide dismutase-inhibitable DEPMPO/hydroxyl radical adducts were generated during the high intraocular pressure period and that the oxidative stress was not increased at reperfusion as assessed by spin trapping and AFR-DMSO measurements. Functional protection provided by free radical scavengers (superoxide dismutase+catalase, TEMPO nitroxide+catalase and dimethylthiourea) against high intraocular pressure-induced electroretinogram alteration confirmed these observations. In conclusion, these experiments demonstrate for the first time by direct measurement that oxygen-derived free radicals are produced by the retina during acute ischemia. This generation could be the explanation for electroretinogram alteration.

Topics: Animals; Ascorbic Acid; Electron Spin Resonance Spectroscopy; Electroretinography; Free Radical Scavengers; Free Radicals; Ischemia; Male; Ocular Hypertension; Rabbits; Reperfusion; Retina; Spin Trapping

Reactive oxygen species (ROS) have been implicated in a variety of pathological processes. The generation of highly reactive oxygen metabolites is an integral feature of normal cellular metabolism (mitochondrial respiratory chain, phagocytosis, arachidonic acid metabolism, ovulation and fertilization), however their production can multiply during pathological circumstances. Free oxygen radicals act either on the extracellular matrix or directly upon cellular membranes themselves. The fundamental defense of the organism against ROS include scavenger enzymes (superoxide dismutase, catalase, glutathione peroxidase) and lipid- and water soluble antioxidant compound (ascorbic acid, glutathione, albumin, transferrin, etc.). Their role in ischemia-reperfusion models have now been comprehensively investigated and it has become clear that ROS is to be blamed for the bulk of post-ischemic injuries, hence the basis for newly established antioxidant therapy in such cases. Also more and more studies have concluded a pivotal role of ROS in degenerative and inflammatory conditions, post-radiation processes and aging. Therefore it seems as we are continuously shedding light on the crucial part played by these molecules regarding a wide range of pathologies, we are discovering new therapeutic windows that would clinically assist us in managing such conditions.

Topics: Aging; Albumins; Antioxidants; Arachidonic Acids; Ascorbic Acid; Catalase; Cell Membrane; Cell Respiration; Extracellular Matrix; Female; Fertilization; Free Radical Scavengers; Free Radicals; Glutathione; Glutathione Peroxidase; Humans; Inflammation; Ischemia; Mitochondria; Ovulation; Phagocytosis; Radiation Injuries; Reactive Oxygen Species; Reperfusion Injury; Superoxide Dismutase; Transferrin

We examined the potential protective effect of pretreatment with corticosteroids or antioxidants (ascorbic acid or allopurinol) in rabbits with reperfusion-induced damage to skeletal muscle after ischemia. 4 hours of limb ischemia induced by a pneumatic tourniquet, followed by reperfusion for 1 hour, caused a considerable amount of ultrastructural damage to the anterior tibialis muscles accompanied by a rise in circulating creatine kinase activity. Pretreatment of animals with depomedrone by a single 8 mg bolus injection led to a preservation of the anterior tibialis structure on both light and electron microscopy. High-dose continuous intravenous infusion with ascorbic acid (80 mg/hr) throughout the period of ischemia and reperfusion also preserved skeletal muscle structure, although allopurinol in various doses had no protective effect. These data are fully compatible with a mechanism of ischemia/reperfusion-induced injury to skeletal muscle, involving generation of oxygen radicals and neutrophil sequestration and activation. They also indicate that damage to human skeletal muscle caused by prolonged use of a tourniquet is likely to be reduced by simple pharmacological interventions.

Topics: Allopurinol; Animals; Anti-Inflammatory Agents; Antimetabolites; Antioxidants; Ascorbic Acid; Ischemia; Methylprednisolone; Methylprednisolone Acetate; Muscles; Rabbits; Reperfusion Injury

Tissue damage in ischemia/reperfusion injury may be mediated by oxidative stress caused by reactive oxidant species. Since such reactive species are difficult to measure directly, changes in antioxidant concentrations are often used as an indication of oxidative stress. In this study, microdialysis membranes were inserted into the livers of anesthetized rats to determine the effects of ischemia/reperfusion on the extra-cellular concentrations of two antioxidants, uric acid and ascorbic acid. Total hepatic ischemia was induced for 30 min by clamping the portal triad and was followed by 60 min of reperfusion. Uric acid and ascorbic acid concentrations were measured in microdialysis perfusates by high-performance liquid chromatography with electrochemical detection. Initial uric acid and ascorbic acid concentrations were high after insertion of membranes into the liver and decreased rapidly within 90 min (P < 0.001; ANOVA with repeated measures). Uric acid concentrations increased over 300% after ischemia and by 600% during the first 30 min of reperfusion (n = 8; P < 0.05). Ascorbic acid concentrations were 60% higher than controls after ischemia and 90% higher during the first 30 min of reperfusion (n = 8; P < 0.05). Alterations in concentrations of these redox-active molecules may be associated with oxidative stress in liver extracellular fluid during ischemia/reperfusion.

Topics: Animals; Ascorbic Acid; Ischemia; Liver; Liver Circulation; Membranes, Artificial; Microdialysis; Osmolar Concentration; Prostheses and Implants; Rats; Rats, Inbred Strains; Reperfusion; Uric Acid

To ascertain whether surgery causes ischaemia-reperfusion (I-R) related injury, if this injury is augmented by preoperative shock, and reduced with low dose allopurinol.. Randomised blind placebo controlled trial.. Surgical laboratory.. 22 pigs were randomly allocated to four groups; OP = operation/placebo, OA = operation/ allopurinol, SOP = shock + operation/placebo, SOA = shock + operation/allopurinol. An aortic tube prosthesis was inserted in all. In groups SOP and SOA preoperative shock was induced by exsanguination. Allopurinol was administered in group OA on the preoperative day and peroperatively, in group SOA during shock and peroperatively.. Perioperative blood concentrations of thiobarbituric acid reactive species (TBARS), ascorbic acid (AA), albumin, 99mTc-albumin and creatine phosphokinase (CPK) as indicators of oxidative membrane damage, antioxidant activity, microvascular permeability changes and muscular cell damage respectively.. In the OP and OA groups TBARS gradually increased, while AA, 99mTc-albumin and CPK remained unchanged and albumin decreased. No effect of allopurinol was observed in these groups. In the SOP group TBARS and AA were not significantly different from groups OP and OA. Yet, albumin, 99mTc-albumin and CPK decreased significantly more in the SOP group. Compared with the SOP group, allopurinol treatment (SOA) produced lower TBARS and higher AA levels, and reduced the effect of shock on albumin, 99mTc-albumin and CPK concentrations.. Aortic surgery causes no I-R related damage. Pre-operative shock produces I-R related damage, which is reduced by allopurinol.

Topics: Allopurinol; Animals; Antioxidants; Aorta, Abdominal; Ascorbic Acid; Blood Vessel Prosthesis; Capillary Permeability; Creatine Kinase; Female; Granulocytes; Ischemia; Muscle, Skeletal; Oxidation-Reduction; Placebos; Random Allocation; Reperfusion Injury; Serum Albumin; Shock; Single-Blind Method; Swine; Technetium; Thiobarbituric Acid Reactive Substances

The in vivo effects of ascorbic acid on the reoxygenated liver tissue were examined, with regard to the following effects: (i) the effects of scavenging radicals and/or reducing peroxidative reactions, and (ii) the effects of the chelation with low-molecular-weight iron and increasing its reactivity (radical production). Ascorbic acid is one of the water-soluble vitamins known to have various physiological effects involving both chelating and reducing properties at once. Lipid peroxidation of the reoxygenated liver tissue estimated by the production of TBARS (thiobarbituric acid-reactive substance) and LPO (lipid hydroperoxides) was suppressed effectively by the preischemic intraperitoneal administration of ascorbic acid. Ascorbic acid also showed this anti-oxidant effect in a dose-dependent manner. The analysis of the levels of ascorbic acid and glutathione of the liver tissue revealed that ascorbic acid works as an anti-oxidant probably by being oxydized finally to dehydroascorbic acid just after the reoxygenation. The latter was reduced to ascorbic acid again, coupled with the conversion of GSH to GSSG in the postischemic time course. The predominant effect of ascorbic acid on the reoxygenated liver tissue seems to be caused by the scavenging radicals and/or reducing peroxidative reactions, rather than by chelating iron and increasing its reactivity (radical production). Cellular integrity (estimated by the release of GOT, GPT, and LDH) and the energy state of the postischemic liver tissue (estimated by the tissue ATP level) were also well preserved by the administration of ascorbic acid.

Topics: Adenosine Triphosphate; Alanine Transaminase; Animals; Ascorbic Acid; Aspartate Aminotransferases; Deferoxamine; Dehydroascorbic Acid; Dose-Response Relationship, Drug; Glutathione; Iron; Ischemia; Kinetics; L-Lactate Dehydrogenase; Lipid Peroxidation; Liver; Male; Rats; Rats, Wistar; Reperfusion Injury; Thiobarbituric Acid Reactive Substances; Time Factors

The measurement of endogenous substances that function as biological antioxidants is of importance because the values obtained might be an index of future health. We quantified three water-soluble antioxidants by high-pressure liquid chromatography with electrochemical detection (h.p.l.c.-e.c.). Current-voltage relationships made at various settings of the D2 porous graphite electrode help to identify ascorbic acid, glutathione and uric acid. The antioxidants are determined simultaneously and without need for derivatization. The method is seen to be useful for comparison of normal rat liver with liver that had undergone oxidative stress through ischaemia. Antioxidant levels in liver, kidney, pancreas and intestinal mucosa are presented and compared with literature values. Endogenous contents of oxidized forms of ascorbic acid and glutathione become apparent following exposure of tissue samples to a strong reductant such as 2-mercapthoethanol.

Topics: Animals; Antioxidants; Ascorbic Acid; Chromatography, High Pressure Liquid; Electrochemistry; Glutathione; Intestinal Mucosa; Ischemia; Kidney; Liver; Mercaptoethanol; Oxidative Stress; Pancreas; Rats; Solubility; Uric Acid; Water

Experience of treatment of 215 patients with obliterating diseases of the vessels in terminal stage using the method of transcatheter medicinal mixtures infusion was summarized. Use of original method permitted to avert the gangrene appearance in 65% of patients, to lower the amputation level--in 15%; in 20% of patients the result was unsatisfactory, high limb amputation was conducted to them.

Topics: Adult; Aged; Amputation, Surgical; Anti-Bacterial Agents; Arterial Occlusive Diseases; Ascorbic Acid; Combined Modality Therapy; Dextrans; Drug Combinations; Heparin; Humans; Infusions, Intra-Arterial; Ischemia; Leg; Middle Aged; Nicergoline; Papaverine; Pentoxifylline; Procaine; Vasodilator Agents; Vitamin B Complex

The aim was to define the following: (1) if reperfusion of ischaemic limbs could cause myocardial damage; (2) if reactive oxygen metabolites are involved in such possible damage.. Ten rats underwent ischaemia-reperfusion of the lower limbs (group A) and 10 underwent the same procedure following treatment with ascorbic acid (group B). Ten rats were used as a control group (group C).. The incidence of severe myocardial mitochondrial damage and serum malondialdehyde concentrations 30 min after reperfusion were both higher in group A than in groups B and C [8/10, 2/10, and 0/10, p < 0.05 and 7.25 (SEM 0.33), 5.30(0.26), and 4.89(0.23) mumol.litre-1, p < 0.05, respectively].. Ischaemia-reperfusion of the lower limbs may cause mitochondrial damage in the myocardium and reactive oxygen metabolites could mediate this damage.

Topics: Animals; Ascorbic Acid; Extremities; Ischemia; Male; Mitochondria, Heart; Rats; Reactive Oxygen Species; Reperfusion; Reperfusion Injury

Using electron spin resonance (ESR) spectroscopy, we examined whether reactive oxygen intermediates (ROIs) are produced after reperfusion of isolated, perfused rat livers subjected to global ischemia (10, 30, 60, and 90 min of ischemia). A few drops of effluent (200 microliters) flowed from reperfused liver was mixed immediately with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO, final concentration 1 M), and ESR measurements were then performed. Immediately after reperfusion, a small amount of ascorbic acid radical and DMPO-OOH, which was formed by the reaction of superoxide with DMPO, was detected. The amount of ascorbic acid radical peaked immediately after reperfusion, but became hardly detectable at 6 min after reperfusion, irrespective of the period of ischemia. Six minutes after reperfusion, not only DMPO-OOH but also DMPO-OH, which was formed by the reaction of hydroxyl radical with DMPO, was detected. Thereafter, DMPO-OOH and DMPO-OH gradually declined and became hardly detectable at 40 min after reperfusion. In accordance with the duration of ischemia, the concentrations of DMPO-OOH and DMPO-OH were highest after 60 min of ischemia, and then after 30, 90, and 10 min of ischemia in decreasing order. These results directly demonstrate that the production of ROIs occurs at an early stage of reperfusion in ischemic liver and that the amount of ROI production is closely related to the duration of ischemia.

Topics: Animals; Ascorbic Acid; Cyclic N-Oxides; Electron Spin Resonance Spectroscopy; Free Radicals; Hydroxyl Radical; In Vitro Techniques; Ischemia; Kinetics; Liver; Male; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Superoxides; Time Factors

The present study set out to investigate whether plasma phosphatidylcholine hydroperoxide (PCOOH) levels could accurately reflect lipid peroxidation linking to liver damage due to ischemia--reperfusion. PCOOH is a primary peroxidative product of phosphatidylcholine (PC), which is the most important functional lipid in the hepatocellular membrane, and may mediate oxidative stress. We quantified PCOOH and PC in the plasma and liver of rats subjected to hepatic ischemia-reperfusion by chemiluminescence detecting HPLC (CL-HPLC) method. Plasma PCOOH levels showed no significant rise in either the ischemia only group or in the sham-operation group, compared to controls (0.7 nmol/mL plasma). At 60 min subsequent to reperfusion, the PCOOH levels in plasma and liver, as well as the levels of several serum markers of liver injury [lactic dehydrogenase (LDH), glutamic-oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT)] increased in proportion to the duration of ischemia (up to 60 min). During periods of reperfusion following 30 min of ischemia, plasma PCOOH increased biphasically (2 nmol/mL; 12-24 hr duration of reperfusion), and generally ran parallel to that in the liver after more than 60 min of reperfusion. Dose-dependent protective effects against warm ischemia (30 min)-reperfusion (12 hr) injury were clearly demonstrated in the groups treated with allopurinol, diclofenac Na, ascorbic acid (V.C), alpha-tocopherol and coenzyme Q10, but not in those treated with r-h-superoxide dismutase or betamethasone. The rises in plasma PCOOH and serum GOT, GPT and LDH of the ischemia-reperfused rats were ameliorated most in the group pretreated with diclofenac Na, and next most in the group pretreated with V.C. These results indicate that the plasma PCOOH levels are a useful index both for liver cell damage induced by oxygen free radicals generated during ischemia-reperfusion, and to investigate the efficacy of drugs against oxidative stress.

Topics: Animals; Ascorbic Acid; Chromatography, High Pressure Liquid; Diclofenac; Free Radicals; Ischemia; Liver; Male; Phosphatidylcholines; Rats; Rats, Wistar; Reperfusion Injury; Time Factors

Oxygen-derived free radicals have been shown to play an important role in reperfusion injury. The protective effect of CV-3611, a new free radical scavenger, on reperfusion injury in an ischemic revascularized hind limb model in rats was examined. Warm ischemia (25 degrees C) was produced by vascular pedicle clamping and sustained for 0, 3, and 6 hr. Histologic and fluorochrome bone-labeling analyses demonstrated improved overall viability of osteocytes, osteoblasts, and marrow cells in the CV-3611-treated group compared to controls. The CV-3611-treated group had statistically significant improvement in the ratio of lacunae, maintained osteogenetic ability, and preserved normal growth plate architecture after 6 hr of ischemia. The control group showed local central areas of disorganization by 3 hr and complete destruction of the growth plate with early growth arrest after 6 hr of ischemia. These results indicate that administration of CV-3611 prior to reperfusion can prevent reperfusion damage in bone tissue and maintain osteogenetic ability. This technique may have clinical application for reducing the complications of prolonged ischemia to bone tissue.

Topics: Animals; Ascorbic Acid; Bone and Bones; Bone Transplantation; Cell Survival; Free Radical Scavengers; Free Radicals; Ischemia; Male; Microsurgery; Osteocytes; Rats; Rats, Inbred Lew; Reperfusion Injury; Superoxides

Topics: Antioxidants; Ascorbic Acid; Brain Diseases; Cardiovascular Diseases; Cells; Free Radical Scavengers; Free Radicals; Humans; Ischemia; Phagocytes; Reactive Oxygen Species; Reperfusion Injury; Respiratory Tract Diseases; Superoxide Dismutase

Lipid peroxidation disrupts membrane integrity and causes structural and functional alterations in ischemic tissues. Taurine and ketamine are putative ischemic protectants that affect Ca2+ influx. Here we report the influence of these compounds on lipid peroxidation in subcellular fractions, isolated cells and intact tissue from bovine retinas. P2 membrane fractions and isolated cells were exposed to the lipid peroxidation inducers cadmium chloride (200 microM) or L-ascorbic acid (1 mM) in the presence of 0-50 mM taurine, 0-10 mM ketamine, 1 mM kynurenic acid or 1 mM dextromethorphan. The latter compounds are N-methyl-D-aspartate receptor antagonists. Lipid peroxidation in isolated eyes reperfused after 1 h of ischemia either with or without protectants was determined by thiobarbituric acid assay. Glutathione was measured in isolated retinas subjected in vitro to simulated ischemia (no glucose or oxygenation) for 60 min either alone or in the presence of taurine or ketamine. Ketamine inhibited chemical- or ischemia-induced lipid peroxidation as well as ischemic glutathione depletion. Under the same conditions, taurine failed to affect lipid peroxidation or glutathione. The data show a direct effect of ketamine on lipid peroxidation and point to separate mechanisms of action for ketamine and taurine.

Topics: Animals; Ascorbic Acid; Cadmium; Cadmium Chloride; Calcium; Cattle; Dextromethorphan; Female; Ischemia; Ketamine; Kynurenic Acid; Lipid Peroxidation; Membrane Lipids; Receptors, N-Methyl-D-Aspartate; Reperfusion Injury; Retina; Taurine; Trifluoperazine

To examine the possible effects of hyperoxalaemia on anaerobic metabolism and erythrocyte pyruvate kinase activity, we induced a rise in plasma oxalate in 11 dialysis patients by the oral administration of ascorbic acid, 500 mg day-1 for 3 weeks. Blood samples were taken from the same antecubital vein before and after the supplementation period, without venous stasis, after an overnight fast. This protocol allowed patients to be used as their own controls. Five healthy subjects underwent an identical protocol to exclude any effect of ascorbate per se. Mean (SEM) plasma oxalate (mumol l-1) rose from 30.3 (3.5) to 48.4 (6.1) in patients and from 1.4 (0.2) to 6.8 (0.9) in healthy subjects. Whole blood ascorbate (mg l-1) rose from 7.0 (0.7) to 26.6 (2.5) in patients and from 9.3 (1.2) to 17.8 (1.8) in healthy subjects (reference range 7.5-20.0 mg l-1). No changes were observed in either group in plasma creatinine, bicarbonate, haemoglobin, or erythrocyte 2,3,diphosphoglycerate (2,3 DPG) after the 3 week supplementation period. Before supplementation lactate generation (area under curve, mmol min l-1) in the 5 min following a 60 s period of standardized ischaemic forearm exercise was significantly (P = 0.026) greater in patients [69.1 (4.7)] than in healthy subjects [46.9 (6.7)]; no significant change in lactate generation occurred in either group after ascorbate-induced hyperoxalaemia. We conclude that changes in plasma oxalate of the order of 20 mumol l-1 have no significant effect on lactate generation or 2,3,DPG levels in uraemic subjects.

Topics: 2,3-Diphosphoglycerate; Adult; Ascorbic Acid; Diphosphoglyceric Acids; Erythrocytes; Forearm; Humans; Ischemia; Lactates; Lactic Acid; Male; Middle Aged; Oxalates; Oxalic Acid; Peritoneal Dialysis, Continuous Ambulatory; Physical Exertion; Renal Dialysis; Uremia

High but well-tolerated doses of the nutritional antioxidants selenium and vitamins E and C have significant immunostimulant, anti-inflammatory, and anti-carcinogenic effects which are well documented in the existing biomedical literature. In addition, these antioxidants help to protect the structural integrity of ischemic or hypoxic tissues, and may have useful anti-thrombotic actions as well. Supplementation with high-dose nutritional antioxidants may eventually gain a broad role in the prevention, treatment, or palliation of cancer, cardiovascular disease, infection, inflammatory disorders, and certain diabetic complications.

Topics: Adjuvants, Immunologic; Animals; Anti-Inflammatory Agents; Antioxidants; Arthritis; Ascorbic Acid; Cardiovascular Diseases; Diabetes Mellitus; Free Radicals; Humans; Hypoxia; Ischemia; Mice; Neoplasms; Rabbits; Rats; Selenium; Superoxides; Thrombosis; Vitamin E

Topics: Abdominal Muscles; Adult; Ascorbic Acid; Diarrhea; Humans; Intestines; Ischemia; Male; Muscle Cramp; Running; Sports Medicine

Topics: Adrenocorticotropic Hormone; Ascorbic Acid; Blood Coagulation Disorders; Diagnosis; Drug Therapy; Fibrinolysis; Humans; Ischemia; Necrosis; Pathology; Prednisone; Promethazine; Purpura; Purpura Fulminans; Tetracycline

Topics: Adrenocorticotropic Hormone; Ascorbic Acid; Blood Coagulation Disorders; Diagnosis; Drug Therapy; Fibrinolysis; Humans; Ischemia; Necrosis; Pathology; Prednisone; Promethazine; Purpura; Purpura Fulminans; Tetracycline