potassium-ascorbyl-tocopheryl-phosphate and Brain-Ischemia

Cerebral ischaemia-reperfusion injury is associated with the generation of reactive oxygen species during the early phases of reoxygenation. EPC-K1, a phosphate diester of vitamins C and E, has been reported to possess potent hydroxyl radical scavenging activity. This study was performed to investigate the effectiveness of EPC-K1 in attenuating cerebral ischaemia-reperfusion injury in a rat model of transient focal cerebral ischaemia.. We evaluated the efficacy of EPC-K1 by measuring the concentration of cerebral thiobarbituric acid reactive substances (TBARS), an indicator of the extent of lipid peroxidation by free radicals, and infarct size in rats subjected to one hour of cerebral ischaemia and 4, 24, or 72 hours of reperfusion.. EPC-K1 significantly reduced both the cerebral TBARS level and the infarct size in a rat model of transient focal cerebral ischaemia. These results indicate that EPC-K1 administration during the early stages of reperfusion ameliorates ischaemic brain injury by inhibiting lipid peroxidation.. This report is the first to describe the protective mechanism of EPC-K1 by measuring both the TBARS level and infarct size in a rat model of transient focal cerebral ischaemia, and may suggest a potential clinical approach for the treatment of ischaemic cerebrovascular disease.

Topics: Animals; Antioxidants; Ascorbic Acid; Brain Ischemia; Disease Models, Animal; Free Radicals; Lipid Peroxidation; Male; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reperfusion Injury; Thiobarbituric Acid Reactive Substances; Vitamin E

EPC-K1, L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl-hydrogen phosphate] potassium salt, is a novel antioxidant. In this study, we investigated a reduction of oxidative neuronal cell damage with EPC-K1 by immunohistochemical analysis for 8-hydroxy-2'-deoxyguanosine (8-OHdG) in rat brain with 60 min transient middle cerebral artery occlusion, in association with terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) and staining for total and active caspase-3. Treatment with EPC-K1 (20 mg kg(-1) i.v.) significantly reduced infarct size (p < 0.05) at 24 h of reperfusion. There were no positive cells for 8-OHdG and TUNEL in sham-operated brain, but numerous cells became positive for 8-OHdG, TUNEL and caspase-3 in the brains with ischemia. The number was markedly reduced in the EPC-K1 treated group. These reductions were particularly evident in the border zone of the infarct area, but the degree of reduction was less in caspase-3 staining than in 8-OHdG and TUNEL stainings. These results indicate EPC-K1 attenuates oxidative neuronal cell damage and prevents neuronal cell death.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Apoptosis; Ascorbic Acid; Brain; Brain Infarction; Brain Ischemia; Caspase 3; Caspases; Deoxyguanosine; DNA Damage; Free Radicals; Immunohistochemistry; In Situ Nick-End Labeling; Infarction, Middle Cerebral Artery; Male; Nerve Degeneration; Neurons; Neuroprotective Agents; Oxidative Stress; Rats; Rats, Wistar; Reperfusion Injury; Vitamin E

Global cerebral ischemia leads morphologically to selective neuronal damage in the CA1 sector of the hippocampus and in the striatum and functionally to a deficit in spatial learning and memory in the water maze. The results of earlier studies which examined the relationship between neuronal damage and the deficits in the water maze were not clear cut. It has been observed, however, that neuroprotection reduces both the deficits in the water maze as well as the neuronal damage. The present study therefore approached the relationship between the neuronal damage and the deficits in water maze using pharmacological means. Global cerebral ischemia was induced in male Wistar rats by four-vessel occlusion for 20 min. Ischemic rats were treated with the N-methyl-D-aspartate receptor antagonist dextromethorphan, 50 mg/kg, with the calcium antagonist levemopamil, 30 mg/kg, with the radical scavenger EPC-K1, 10 mg/kg, or with solvent. Treatment with dextromethorphan or levemopamil reduced the deficit in spatial learning by limiting the increase in swim distance due to ischemia. Both substances also reduced the deficit in spatial memory by minimizing the ischemia-induced reduction in time spent in the quadrant of the former platform position during the probe trial. EPC-K1 had no influence on the ischemia-induced behavioural changes. Group comparisons demonstrated that the swim speed and the percentage of the swimming path along the sidewall were affected neither by ischemia nor by any of the treatments. Histological examination revealed neuronal damage in the hippocampus and in the striatum in all of the ischemic rats. Treatment with dextromethorphan or levemopamil reduced the hippocampal damage by 32% and 36%, respectively. In addition, dextromethorphan diminished the striatal damage about 78%. Correlation analysis demonstrated a correlation between the cumulative swim distance of all 20 escape trials and hippocampal damage (r = 0.65, P < 0.001) but not between swim distance and striatal damage (r = 0.14, P = 0.364). No correlation was found between quadrant time of the probe trial and either hippocampal damage (r = -0.21, P = 0.19) or striatal damage (r = -0.02, P = 0.889). The average percentage of the swimming path along the side wall related to the hippocampal damage (r = 0.28, P = 0.035) but not to the striatal damage (r = 0.05, P = 0.381). With respect to the average swim speed a correlation to striatal damage was observed (r = -0.69, P < 0.001) but not to hi

Topics: Animals; Antioxidants; Ascorbic Acid; Behavior, Animal; Brain Ischemia; Calcium Channel Blockers; Dextromethorphan; Male; Maze Learning; Memory; Neurons; Neuroprotective Agents; Rats; Rats, Wistar; Receptors, N-Methyl-D-Aspartate; Verapamil; Vitamin E

The purpose of the present study was to determine after what time period hydroxyl radical formation contributes most to ischemic brain damage in focal ischemia, using a hydroxyl radical scavenger, EPC-K1, L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyl-tridecyl)-2H-1-be nzopyran-6yl-hydrogen phosphate] potassium salt. Focal ischemia was produced by thrombotic occlusion of the left middle cerebral artery in rats. After evaluation of the pharmacokinetics of EPC-K in the brain tissue and plasma following 10 mg/kg intravenous bolus treatment of conscious rats, we investigated the neuroprotective effect of EPC-K1 in the middle cerebral artery occlusion model. A single intravenous bolus of EPC-K1 was given immediately, 3 or 6 h after ischemia, and cerebral brain damage was measured 24 h after ischemia. When EPC-K1 was injected 3 h after ischemia, a significant (P < 0.01) reduction of cerebral brain damage was observed. EPC-K1 delivered by intravenous infusion that started immediately after ischemia and lasted for 24 h, also significantly (P < 0.05) reduced brain damage, but the efficacy of the neuroprotective effect was the same as that of the 3 h after ischemia bolus treatment. These results may indicate that the period of hydroxyl radical formation most critical for ischemic brain damage is a few hours after the third hour following ischemia in this model.

Topics: Animals; Ascorbic Acid; Brain Ischemia; Free Radical Scavengers; Hydroxyl Radical; Male; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Vitamin E

Effect of L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H -1- benzopyran-6yl-hydrogen phosphate] potassium salt (EPC-K1, CAS 127061-56-7), a diester of alpha-tocopherol and ascorbic acid, on transient cerebral ischemia was studied in Mongolian gerbils. Cerebral energy metabolism and intracellular pH (pHi) were estimated employing in vivo 31P nuclear magnetic resonance (NMR) spectroscopy. Intraperitoneal injection of EPC-K1 (5 or 10 mg/kg) prior to ischemia significantly ameliorated pHi reduction in a dose dependent manner during ischemia. After reperfusion, energy and pHi recoveries were significantly faster in the EPC-K1 groups than in the control group. EPC-K1 (10 mg/kg) significantly reduced the extent of cerebral edema. Moreover, administration of EPC-K1 immediately after reperfusion significantly shortened the consciousness recovery in a dose dependent manner. The results suggest that EPC-K1 may exert protective effects on ischemic brain and may have therapeutic value in ischemic stroke.

Topics: Animals; Ascorbic Acid; Brain Chemistry; Brain Edema; Brain Ischemia; Consciousness; Dose-Response Relationship, Drug; Energy Metabolism; Gerbillinae; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Male; Vitamin E