EPC-KI, L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran6-yl-hydrogen phosphate] potassium salt, is a novel antioxidant. In this study, we investigated a reduction of oxidative neuronal cell damage with EPC-KI 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-Kl (20 mg kg^sup -1^ i.v.) significantly reduced infarct size (p
Keywords: EPC-KI; ischemia; 8-OHdG,- TUNEL; caspase-3
L-ascorbic acid (vitamin C) and a-tocopherol (vitamin E), two endogenous antioxidants, are important members of nonenzymatic antioxidant defense systems. However, as vitamin E is insoluble in water, its water-soluble analogs are synthesized in order to improve its absorption. EPCK1, L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl2-(4,8,12-trimethyltridecly)-2H-1 -benzopyran-6-yl-hydrogen phosphate] potassium salt, is a novel phosphate ester of vitamin C and vitamin E, which is soluble in both water and lipid1. It was reported2 that EPC-Kl could act as a scavenger of hydroxyl radicals and an inhibitor of lipid peroxidation. Hydroxyl radical is highly reactive, and oxidizes cellular lipids, protein and nucleic acids, leading to cell death3,4. Under physiological condition, superoxide and hydrogen peroxide are constantly scavenged by superoxide dismutase (SOD), glutathione peroxidase, and catalase. Under condition of ischemia, however, an overproduction of oxygen free radicals perturbs the antioxidative defense mechanisms, and hydroxyl radicals are generated. Studies have shown that radical scavengers and inhibitors of lipid peroxidation can ameliorate ischemic neuronal damages-13. Indeed, previous study14 demonstrated that EPC-K1 reduced ischemic brain damage. However, the mechanism of its neuroprotective effect had been unclear.
The current study demonstrated that the ameliorative effect of EPC-K1 on ischemic brain injury was associated with reduction of 8-OHdG-, TUNEL-, total and active caspase-3-positive cells.
This work was partly supported by Grants-in-Aid for Scientific Research on 12877211 and 12470141 from the Ministry of Educaiton, Japan, and grants from Japan Brain Foundation, Takeda Medical Research Foundation, and Japan Heart Association.
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W.R. Zhang, T. Hayashi, C. Sasaki, K. Sato, 1. Nagano, Y. Manabe and K. Abe Department of Neurology, Okayama University School of Medicine and Dentistry, Okayama, Japan
Correspondence and reprint requests to: Prof. Abe, MD, PhD, Department of Neurology, Okayama University Medical School, 2-5-1 Shikatacho, Okayama 700-8558, Japan.
[email@example.com] Accepted for publication December 2000.
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