title: Effects of low-intensity ultrasound on gramicidin D-induced erythrocyte edema.
abstract: OBJECTIVE
  To determine whether low-intensity ultrasound (US) can reduce red blood cell (RBC) edema and, if so, whether the US activity is associated with aquaporin 1 (AQP-1), a water channel in the cell membrane.
  
  
  METHODS
  Red blood cell edema was induced by gramicidin D treatment at 40 ng/mL for 20 minutes and evaluated by a hematocrit assay. Low-intensity continuous wave US at 1 MHz was applied to RBCs for the last 10 minutes of gramicidin D treatment. To determine whether US activity was associated with AQP-1, RBCs were treated with 40 μM mercuric chloride (HgCl(2)), an AQP-1 inhibitor, for 20 minutes at the time of gramicidin D treatment. Posttreatment morphologic changes in RBCs were observed by actin staining with phalloidin.
  
  
  RESULTS
  Red blood cell edema increased significantly with gramicidin D at 20 (1.8%), 40 (6.7%), 60 (16.7%), and 80 (11.3%) ng/mL, reaching a peak at 60 ng/mL, compared to the control group (20 ng/mL, P = .019; 40, 60, and 80 ng/mL, P < .001). No significant RBC hemolysis was observed in any group. Edema induced by gramicidin D at 40 ng/mL was significantly reduced by US at 30 (3.4%; P = .003), 70 (4.4%; P = .001), and 100 (2.9%; P = .001) mW/cm(2). Subsequent experiments showed that edema reduction by US ranged from 7% to 10%. Cotreatment with HgCl(2) partially reversed the US effect and showed a significantly different level of edema compared to gramicidin D-alone and US-cotreated groups (P = .001). These results were confirmed by microscopic observation of RBC morphologic changes.
  
  
  CONCLUSIONS
  Low-intensity US could reduce gramicidin D-induced RBC edema, and its effect appeared to at least partly involve regulation of AQP-1 activity. These results suggest that low-intensity US can be used as an alternative treatment to control edema and related disorders.
authors.affiliation: Department of Physiology (M.H.L., A.R.S., S.R.P.), Inha Research Institute for Medical Sciences (J.K.), and Division of Biomedical and Bioengineering Sciences (B.H.C.), Inha University College of Medicine, Incheon, Korea; and Departments of Orthopedic Surgery (B.-H.M.) and Physiology (E.J.B.), Ajou University School of Medicine, Suwon, Korea.
authors.forename: Mi Hyun
authors.initials: MH
authors.lastname: Lim
authors.affiliation: Department of Physiology (M.H.L., A.R.S., S.R.P.), Inha Research Institute for Medical Sciences (J.K.), and Division of Biomedical and Bioengineering Sciences (B.H.C.), Inha University College of Medicine, Incheon, Korea; and Departments of Orthopedic Surgery (B.-H.M.) and Physiology (E.J.B.), Ajou University School of Medicine, Suwon, Korea.
authors.forename: A Rum
authors.initials: AR
authors.lastname: Seo
authors.affiliation: Department of Physiology (M.H.L., A.R.S., S.R.P.), Inha Research Institute for Medical Sciences (J.K.), and Division of Biomedical and Bioengineering Sciences (B.H.C.), Inha University College of Medicine, Incheon, Korea; and Departments of Orthopedic Surgery (B.-H.M.) and Physiology (E.J.B.), Ajou University School of Medicine, Suwon, Korea.
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Physiology (M.H.L., A.R.S., S.R.P.), Inha Research Institute for Medical Sciences (J.K.), and Division of Biomedical and Bioengineering Sciences (B.H.C.), Inha University College of Medicine, Incheon, Korea; and Departments of Orthopedic Surgery (B.-H.M.) and Physiology (E.J.B.), Ajou University School of Medicine, Suwon, Korea.
authors.forename: Byoung-Hyun
authors.initials: BH
authors.lastname: Min
authors.affiliation: Department of Physiology (M.H.L., A.R.S., S.R.P.), Inha Research Institute for Medical Sciences (J.K.), and Division of Biomedical and Bioengineering Sciences (B.H.C.), Inha University College of Medicine, Incheon, Korea; and Departments of Orthopedic Surgery (B.-H.M.) and Physiology (E.J.B.), Ajou University School of Medicine, Suwon, Korea.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Baik
authors.affiliation: Department of Physiology (M.H.L., A.R.S., S.R.P.), Inha Research Institute for Medical Sciences (J.K.), and Division of Biomedical and Bioengineering Sciences (B.H.C.), Inha University College of Medicine, Incheon, Korea; and Departments of Orthopedic Surgery (B.-H.M.) and Physiology (E.J.B.), Ajou University School of Medicine, Suwon, Korea.
authors.forename: So Ra
authors.initials: SR
authors.lastname: Park
authors.affiliation: Department of Physiology (M.H.L., A.R.S., S.R.P.), Inha Research Institute for Medical Sciences (J.K.), and Division of Biomedical and Bioengineering Sciences (B.H.C.), Inha University College of Medicine, Incheon, Korea; and Departments of Orthopedic Surgery (B.-H.M.) and Physiology (E.J.B.), Ajou University School of Medicine, Suwon, Korea. bryan@inha.ac.kr.
authors.forename: Byung Hyune
authors.initials: BH
authors.lastname: Choi
mesh_terms: D000818:Animals; D051398:Aquaporin 1 / Q000378:metabolism* / Q000528:radiation effects; D001834:Body Water / Q000378:metabolism*; D048429:Cell Size / Q000187:drug effects / Q000528:radiation effects*; D002478:Cells, Cultured; D004912:Erythrocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D006096:Gramicidin / Q000494:pharmacology*; D019220:High-Energy Shock Waves; D015640:Ion Channel Gating / Q000187:drug effects / Q000528:radiation effects; D008297:Male; D064587:Osmoregulation / Q000187:drug effects / Q000528:radiation effects; D011829:Radiation Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D014464:Ultrasonic Therapy / Q000379:methods*
chemical_list: C496022:Aqp1 protein, rat; D006096:Gramicidin; D051398:Aquaporin 1
keywords: aquaporin 1; basic science; edema; gramicidin D; low-intensity ultrasound; water transport