linoleic-acid and Reperfusion-Injury

Icaritin (ICT) has been previously demonstrated to display protective effects against cerebral ischemic reperfusion (I/R) by inhibiting oxidative stress, but the mechanism remains unclear. This study aimed to explore the mechanism from the perspective of metabolomics.. A mice cerebral artery occlusion/reperfusion (MCAO/R) model was explored to mimic cerebral ischemic reperfusion and protective effect of ICT was assessed by neurologic deficit scoring, infarct volume and brain water content. Ultra-high-performance liquid chromatography electrospray ionization orbitrap tandem mass spectrometry (UHPLC-ESI-QE-Orbitrap-MS) based metabolomic was performed to explore potential biomarkers. Brain tissue metabolic profiles were analyzed and metabolic biomarkers were identified through multivariate data analysis. The protein levels of Nrf2, HO-1 and HQO1 were assayed by western blot. The release of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were detected using corresponding assay kits.. The results showed that after ICT treatment, the neurological deficit, cerebral infarction area, brain edema and the level of MDA in brain tissue of MCAO/R mice were significantly reduced. Meanwhile, ICT enhanced the activity of SOD, CAT and GSH-Px. Western blot results confirmed that ICT up-regulated the protein levels of antioxidant-related protein including Nrf2, HO-1 and NQO1. According to the metabolomic profiling of brain tissues, clear separations were observed among the Sham, Model and ICT groups. A total of 44 biomarkers were identified, and the identified biomarkers were mainly related to linoleic acid metabolism, arachidonic acid metabolism, alanine, aspartate and glutamate metabolism, arginine biosynthesis, arginine and proline metabolism, D-glutamine and D-glutamate metabolism, taurine and hypotaurine metabolism and purine metabolism, respectively. At the same time, the inhibitory effect of ICT on arachidonic acid and linoleic acid in brain tissue, as well as the promoting effect on taurine, GABA, NAAG, may be the key factors for the anti-neurooxidative function of mice after MCAO/R injury.. Our results demonstrate that ICT has benefits for MCAO/R injury, which are partially related to the suppression of oxidative stress

Topics: Animals; Antioxidants; Arachidonic Acid; Chromatography, High Pressure Liquid; gamma-Aminobutyric Acid; Linoleic Acid; Mice; NF-E2-Related Factor 2; Reperfusion; Reperfusion Injury; Superoxide Dismutase; Taurine

Autofluorescence (AF) of crude serum was investigated with reference to the potential of its intrinsic AF biomarkers for the noninvasive diagnosis of liver injury. Spectral parameters of pure compounds representing retinol (vitamin A) and fluorescing free fatty acids were characterized by spectrofluorometry, to assess spectral parameters for the subsequent AF analysis of serum, collected from rats undergoing liver ischemia/reperfusion (I/R). Differences in AF spectral profiles detected between control and I/R were due to the increase in the AF components representing fatty acids in I/R serum samples. No significant changes occurred for retinol levels, consistently with the literature reporting that constant retinol levels are commonly observed in the blood, except for malnutrition or chronic severe liver disease. Conversely, fatty acids, in particular arachidonic and linoleic acid and their derivatives, act as modulating agents in inflammation, representing both a protective and damaging response to stress stimuli. The biometabolic and pathophysiological meaning of serum components and the possibility of their direct detection by AF spectrofluorometry open up interesting perspectives for the development of AF serum analysis, as a direct, cost effective, supportive tool to assess liver injury and related systemic metabolic alterations, for applications in experimental biomedicine and foreseen translation to the clinics.

Topics: Animals; Arachidonic Acid; Biomarkers; Disease Models, Animal; Energy Metabolism; Fatty Acids; Fluorescence; Inflammation; Ischemia; Linoleic Acid; Liver; Liver Diseases; Male; Rats; Rats, Wistar; Reperfusion Injury; Serum; Spectrometry, Fluorescence; Vitamin A

Induced erythrocyte membrane peroxidation (EMP) is considered as an accurate model of reperfusion injuries and as such was used to investigate protective effects of various drugs. EMP was induced by an azo initiator and monitored by oxygen uptake. Both hydrophilic (ascorbic acid) and lipophilic (alpha-tocopherol, probucol, nicanartine) chain-breaking antioxidants as well as ferriheme-bound drugs (deferoxamine, chloroquine) inhibited EMP. When antioxidants and ferriheme-bound drugs were combined, synergistic effects were observed. It is proposed that ferriheme compounds which catalyse peroxide induced lipid peroxidation were blocked by deferoxamine and/or chloroquine. So these drugs inhibited at least partly the membrane peroxidation process and added their effects to the ones of chain-breaking antioxidants.

Topics: Adult; Amidines; Antioxidants; Ascorbic Acid; Chloroquine; Deferoxamine; Drug Synergism; Erythrocyte Membrane; Fatty Acids; Female; Hemin; Humans; Linoleic Acid; Lipid Peroxidation; Male; Membrane Lipids; Oxidation-Reduction; Oxygen Consumption; Oxyhemoglobins; Probucol; Pyridines; Reperfusion Injury; Vitamin E

Hyperlipidemia is frequently associated with hyperinsulinemia, but because the effects of fatty acids on insulin secretion in in vitro studies using isolated perifused islets have mostly been described with supraphysiological concentrations of fatty acids, it has remained uncertain whether elevated lipid levels contribute to hyperinsulinemia by their direct stimulation of insulin secretion. In the present study, we have identified reoxygenation injury in isolated islet function as a contributing factor in the failure of physiological concentrations of free fatty acids to stimulate insulin secretion in isolated perifused islets. Reoxygenation of isolated islets is associated with the production of reactive oxygen species, which impair islet function. We have found that pretreatment of freshly isolated islets with the antioxidant glutathione (GSH), as well as a 24-hour preculture of isolated islets under appropriate conditions, enhanced their sensitivity to fatty acid stimulation.

Topics: Animals; Cell Separation; Cells, Cultured; Diffusion Chambers, Culture; Fatty Acids; Female; Insulin; Insulin Secretion; Islets of Langerhans; Linoleic Acid; Mice; Organ Culture Techniques; Oxygen; Palmitates; Reperfusion Injury

Rats were fed diets containing different ratios of linoleate (18:2 n-6) to alpha-linolenate (18:3 n-3), and the severity of gastric injury induced by ethanol, ischemia/reperfusion and water-immersion stress was compared. On decreasing the 18:2 n-6/18:3 n-3 ratios in the diets, the proportion of arachidonic acid (20:4 n-6) decreased and that of eicosapentaenoic acid (20:5 n-3) increased in the phospholipids of the gastric mucosa, which was associated with decreased mucosal prostaglandin E2 content. Mucosal injury in all the three experimental models was exacerbated significantly in the diet group fed 18:2 n-6/18:3 n-3 ratio of 0.25 (perilla oil) as compared with the groups fed dietary oils with 18:2 n-6/18:3 n-3 ratios of 2.7 (mixture of perilla and safflower oils) and 127 (safflower oil). This adverse effect induced by perilla oil diet was not observed when rats were pretreated with a mild irritant (20% ethanol) prior to challenge with a strong irritant (absolute ethanol). Furthermore, an 18:2 n-6/18:3 n-3 ratio of as low as 1 was found to be in a safe range in the water-immersion stress ulcer model. Thus, oils with very low n-6/n-3 ratios, for example perilla oil, could be used without the risk of the observed adverse effects on experimental gastric injury in people of industrialized countries ingesting foods with n-6/n-3 ratios of above 4. A decrease in the n-6/n-3 ratios to 2 or below is still recommended for the prevention of chronic diseases in the elderly related to atherosclerosis and inflammation.

Topics: alpha-Linolenic Acid; Animals; Diet; Dietary Fats, Unsaturated; Dinoprostone; Disease Models, Animal; Ethanol; Fatty Acids; Gastric Acid; Gastric Mucosa; Linoleic Acid; Male; Pepsin A; Phospholipids; Plant Oils; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Stomach Ulcer

We found that cytochrome c (Cyt c) could oxidize cardiolipin (CL), and detected monoepoxides of linoleic acid (LA) in the fatty acids constituting the oxidized CL. We also found that in the presence of CL and Cyt c, free LA was oxidized and LA monoepoxides were produced. The aim of this study was to elucidate the mechanism of this lipid peroxidation. We concluded that ferric Cyt c produced some radical species from water-soluble oxygen in the presence of CL (CL-Cyt c system) and that radicals oxidized free LA or CL. The CL-Cyt c system may be another LA monoepoxide producing system in the neutrophil and may account for the lipid peroxidation observed in the ischemia-reperfusion-induced cardiac injury.

Topics: Cardiolipins; Chromatography, High Pressure Liquid; Cytochrome c Group; Epoxy Compounds; Exotoxins; Ferrous Compounds; Gas Chromatography-Mass Spectrometry; Linoleic Acid; Linoleic Acids; Lipid Peroxides; Oxidation-Reduction; Reperfusion Injury; Spectrum Analysis

We describe the use of two in vitro tests to characterize plasma antioxidant capacity at the time of cardiac bypass in operations for congenital heart disease in 30 patients aged 3 days to 16 years (average 4.4 +/- 0.9 years [standard error]). Bypass and crossclamp time, circuit volume, and type of operation were recorded for each patient. First, a test of plasma radical antioxidant power measured chain breaking (secondary) antioxidant capacity of plasma to prevent oxidation of linoleic acid in vitro. Second, overall ability of plasma to prevent lipid peroxidation was assessed by a classic test of plasma inhibition of malondialdehyde formation in a beef brain homogenate. Plasma total radical antioxidant power level at baseline was 0.74 +/- 0.03 mumol/ml plasma, which decreased to 0.15 +/- 0.05 mumol/ml plasma after bypass (p < 0.001) and 0.26 +/- 0.08 mumol/ml plasma with recovery (n = 18, p < 0.001). Analysis of variance of postbypass total radical antioxidant power value showed age (p = 0.0002, r = 0.63) and bypass time (p = 0.009, r = 0.4677) to be significant factors. Pump prime volume in milliliters per kilogram and preoperative hemoglobin value were not significant factors. Beef brain malondialdehyde formation in vitro was limited 92% +/- 3% by normal plasma before operation versus 53% +/- 5% after operation (p < 0.001) and 51% +/- 5% at recovery after arrival in the pediatric intensive care unit (p < 0.001). Analysis of variance of the changes from before to after operation showed age p = 0.0015, r = 0.55) and bypass time (p = 0.033, r = 0.39) to be significant factors. Thus antioxidant capacity of plasma is significantly diminished after cardiopulmonary bypass in children. Young patient age and long duration of cardiopulmonary bypass are identified as factors that correlate positively with depletion of antioxidant capacity with bypass.

Topics: Adolescent; Analysis of Variance; Animals; Antioxidants; Brain; Cardiopulmonary Bypass; Cattle; Child; Child, Preschool; Heart Defects, Congenital; Humans; In Vitro Techniques; Infant; Infant, Newborn; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Malondialdehyde; Oxidation-Reduction; Oxygen Consumption; Postoperative Period; Reperfusion Injury

The free radical-scavenging activity of captopril and ascorbic acid was determined by assessing their ability to inhibit the peroxidation of linoleic acid in sodium dodecyl sulphate (SDS) micelles at 37 degrees C. The extent of peroxidation was monitored polarographically using an oxygen electrode to determine oxygen consumption rates. Ascorbic acid was observed to inhibit the peroxidation in a concentration-dependent fashion with an IC50 value of 17 microM. In contrast, the addition of captopril at concentrations up to 500 microM did not result in any detectable inhibition. Unlike ascorbic acid, no synergistic effect, as evidenced by the duration of inhibition, was observed with captopril/alpha-tocopherol mixtures. Measurements of the partitioning of captopril between SDS micelles and the aqueous phase show that 37% of the bulk captopril concentration is localized within the micellar phase; this indicates that phase separation of captopril from the lipid peroxyl radicals is not the cause of the observed lack of inhibitory activity.

Topics: Angiotensin-Converting Enzyme Inhibitors; Ascorbic Acid; Captopril; Diffusion; Free Radical Scavengers; Linoleic Acid; Linoleic Acids; Lipid Peroxidation; Micelles; Oxidation-Reduction; Oxygen Consumption; Phospholipids; Reperfusion Injury; Sodium Dodecyl Sulfate