title: Low intensity ultrasound inhibits brain oedema formation in rats: potential action on AQP4 membrane localization.
abstract: OBJECTIVE
  Brain oedema is a major contributing factor to the morbidity and mortality of a variety of brain disorders. Although there has been considerable progress in our understanding of pathophysiological and molecular mechanisms associated with brain oedema so far, more effective treatment is required and is still awaited. Here we intended to study the effects of low intensity ultrasound (LIUS) on brain oedema.
  
  
  METHODS
  We prepared the rat hippocampal slice in vitro and acute water intoxication in vivo models of brain oedema. We applied LIUS stimulation in these models and studied the molecular mechanisms of LIUS action on brain oedema.
  
  
  RESULTS
  We found that LIUS stimulation markedly inhibited the oedema formation in both of these models. LIUS stimulation significantly reduced brain water content and intracranial pressure resulting in increased survival of the rats. Here, we showed that the AQP4 localization was increased in the astrocytic foot processes in the oedematous hippocampal slices, while it was significantly reduced in the LIUS-stimulated hippocampal slices. In the in vivo model too, AQP4 expression was markedly increased in the microvessels of the cerebral cortex and hippocampus after water intoxication but was reduced in the LIUS-stimulated rats.
  
  
  CONCLUSIONS
  These data show that LIUS has an inhibitory effect on cytotoxic brain oedema and suggest its therapeutic potential to treat brain oedema. We propose that LIUS reduces the AQP4 localization around the astrocytic foot processes thereby decreasing water permeability into the brain tissue.
authors.affiliation: Department of Physiology, Inha University College of Medicine, Incheon, Korea.
authors.forename: Mrigendra Bir
authors.initials: MB
authors.lastname: Karmacharya
authors.affiliation: Department of Physiology, Inha University College of Medicine, Incheon, Korea.
authors.forename: Kil Hwan
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Physiology, Inha University College of Medicine, Incheon, Korea.
authors.forename: See Yoon
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Joonho
authors.initials: J
authors.lastname: Chung
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Ajou University, Suwon, Korea.
authors.forename: Byoung-Hyun
authors.initials: BH
authors.lastname: Min
authors.affiliation: Department of Physiology, Inha University College of Medicine, Incheon, Korea.
authors.forename: So Ra
authors.initials: SR
authors.lastname: Park
authors.affiliation: Department of Biomedical Sciences, Inha University College of Medicine, Incheon, Korea.
authors.forename: Byung Hyune
authors.initials: BH
authors.lastname: Choi
mesh_terms: D000818:Animals; D051401:Aquaporin 4 / Q000378:metabolism*; D001253:Astrocytes / Q000378:metabolism; D001929:Brain Edema / Q000000981:diagnostic imaging* / Q000378:metabolism; D006624:Hippocampus / Q000000981:diagnostic imaging* / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015996:Survival Rate; D014463:Ultrasonography; D014867:Water / Q000032:analysis
chemical_list: C496032:Aqp4 protein, rat; D051401:Aquaporin 4; D014867:Water
keywords: aquaporin 4 (AQP4); brain oedema; intracranial pressure (ICP); low intensity ultrasound (LIUS); oxygen glucose deprivation (OGD); water content