KR-31378 protects neurons from ischemia-reperfusion brain injury by attenuating lipid peroxidation and glutathione loss.
Neuronal hyperexcitability and oxidative stress play critical roles in neuronal cell death in stroke. Therefore, we studied the effects of (2S,3S,4R)-N?-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-benzylguanidine (KR-31378), possessing both antioxidant and K(+) channel-modulating activities, on brain ischemia-reperfusion injury models. Treatment with KR-31378 (30 mg/kg, i.v.) significantly reduced infarct area and edema by 24% and 36%, respectively, in rats subjected to 2 h of middle cerebral artery occlusion and 22 h of reperfusion with significant attenuation of elevated lipid peroxidation (99% of normal) and glutathione loss (60% of normal) in ischemic hemisphere. We further studied its neuroprotective mechanism in fetal rat primary mixed cortical culture. Incubation of cortical neurons with KR-31378 protected FeSO(4)-induced cell death in a concentration-dependent manner (IC(50)=12 microM). Its neuroprotective effect was neither mimicked by other K(+) channel openers nor abolished in the presence of ATP-dependent K(+) channel (K(ATP)) blockers, indicating that its effect was not related to K(+) channel opening activity. The mechanism of protection is rather attributable to the antioxidant property of KR-31378 since it suppressed the intracellular accumulation of reactive oxygen species and ensured lipid peroxidation by 120% and 80%, respectively, caused by FeSO(4). We further studied its effect on antioxidant defense, enzymatic and nonenzymatic systems. Treatment of neurons with FeSO(4) resulted in decrease of catalase (8% of control) and glutathione peroxidase (14% of control) activities, which were restored by KR-31378 treatment (70% and 57% of control, respectively). In addition, it attenuated the depletion of glutathione contents (60% of control) caused by FeSO(4). These results suggest that KR-31378 exerts a beneficial effect in focal ischemia, which may be attributed to its antioxidant property.
Kim
Sun-Ok
SO
Agropharma Research Institute, Dongbu Hannong Chemical Co., 103-2 Moonji-dong, Yusung, Daejeon 305-708, South Korea. sokim_99@msn.com
Cho
In Sun
IS
Gu
Hee Kyoung
HK
Lee
Dong Ha
DH
Lim
Hong
H
Yoo
Sung-Eun
SE
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism; D001929:Brain Edema / Q000473:pathology / Q000517:prevention & control; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects; D005609:Free Radicals / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D006146:Guanidines / Q000627:therapeutic use*; D020244:Infarction, Middle Cerebral Artery / Q000473:pathology / Q000517:prevention & control; D007501:Iron / Q000037:antagonists & inhibitors / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018696:Neuroprotective Agents; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D015221:Potassium Channels / Q000819:agonists*; D011714:Pyrans / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000378:metabolism* / Q000473:pathology*
D000975:Antioxidants; D005609:Free Radicals; D006146:Guanidines; C438686:N''-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-benzylguanidine; D018696:Neuroprotective Agents; D015221:Potassium Channels; D011714:Pyrans; D007501:Iron; D005978:Glutathione