• Ryuichi Katada, Yoko Nishitani, Osamu Honmou, Keisuke Mizuo, Shunichiro Okazaki, Kenji Tateda, Satoshi Watanabe, and Hiroshi Matsumoto.
• Department of Legal Medicine and Molecular Alcohology, Sapporo Medical University School of Medicine, Sapporo, Japan.
• Am. J. Pathol. 2012 Jan 1; 180 (1): 17-23.

AbstractWe previously reported that ethanol consumption affects morbidity and mortality after traumatic brain injury (TBI) by accelerating brain edema via oxidative stress after TBI. Aquaporin-4 (AQP4), a water channel, is involved in brain edema formation. In this study, we found that acute ethanol administration increased AQP4 expression after TBI, leading to severe brain edema in rats. Rats were pretreated with ethanol (3 g/kg) or dl-buthionine-(S,R)-sulfoximine (BSO; 100 mg/kg), an oxidative stressor, before TBI. Acetazolamide, an AQP4 inhibitor, was administered to ethanol-pretreated rats 3 or 12 hours after TBI. Brain edema was increased 24 hours after TBI in both the ethanol- and BSO-pretreated groups. Ethanol pretreatment induced lipid peroxidation 24 hours after TBI. Transcription factors, NF-κB and hypoxia-inducible factor-1α, were activated 3 and 24 hours after TBI in the BSO- and ethanol-pretreated groups, respectively. In the ethanol-pretreated group, AQP4 was accumulated, particularly in astrocyte end feet, 24 hours after TBI. Acetazolamide treatment improved the survival rate to 100% and decreased brain edema and AQP4 in ethanol-pretreated rats. These findings suggest that ethanol induces up-regulation of AQP4, leading to brain edema. The accumulation of AQP4 may play an important role in the augmentation of brain edema after TBI under ethanol consumption.Copyright © 2012 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

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