title: Methods of measuring volume changes in erythrocytes under hypoosmotic stress: a comparison.
abstract: OBJECTIVE
  To compare methods of analyzing changes in red blood cell volume when exposed to osmotic challenge.
  
  
  METHODS
  The sensitivity of different methods was tested using fish erythrocytes under hypoosmotic stress (80% and 60% saline): hematocrit ratio, Hcto(exp)/ Hcto(ctr); cellular hemoglobin mean concentration; optical density (OD400); water content; surface area estimation; mean corpuscular volume (MCV); and mean cellular hemoglobin (MCH).
  
  
  RESULTS
  Cells exposed to both solutions demonstrated a volume increase via hematocrit ratio of 16 +/- 2% and 30 +/- 3% (p < 0.001) when exposed to 80% and 60% saline, respectively. Cellular volume estimation by OD400 revealed a change in volume only at 60% saline (26% increase). Surface area estimation suggested a difference in volume at 60% saline. MCV revealed differences in volume at < 60% saline exposure with a 33% increase and indicated a 19% increase at 80% saline. MCH showed an increase of 48% with exposure to 80% saline.
  
  
  CONCLUSIONS
  The results reveal that Hcto(ctr)/Hcto(exp), MCV, OD400 and MCH yield significant volume changes and that Hcto(ctr)/Hcto(exp) is the most sensitive assay.
authors.affiliation: Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Panis
authors.forename: Marta M
authors.initials: MM
authors.lastname: Souza
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000502:physiology; D048429:Cell Size; D004912:Erythrocytes / Q000166:cytology*; D005399:Fishes; D006400:Hematocrit / Q000379:methods*; D009997:Osmotic Pressure