title: Red blood cell damage after trauma-hemorrhage is modulated by gender.
abstract: BACKGROUND
  Previous studies have shown that trauma-hemorrhagic shock (T/HS) causes significant alterations in red blood cell (RBC) deformability and shape. Gender is becoming well recognized as a modulating factor in the pathophysiologic response to trauma. We hypothesize that female subjects are more resistant to adverse effects of T/HS on RBC deformability and shape than male subjects because of estrogen protection.
  
  
  METHODS
  Elongation index, a measure of RBC deformability, was examined in six male rats and four groups of female rats at different stages of the estrous cycle (six animals per group) before and 6 hours after T/HS by laser ektacytometry. RBC shape was determined by scanning electron microscopy. Lipid peroxidation was evaluated by measurement of malonyldialdehyde in plasma 6 hours after T/HS.
  
  
  RESULTS
  Male rats had a significant decrease in RBC elongation index after T/HS as compared with preshock values. RBC deformability of the proestrous (PES) and estrous female rats did not decrease after T/HS. Postshock RBC deformability values in metestrous and diestrous female rats did not differ from male rats. Male rats and metestrous and diestrous females had a significant increase in the percentage of abnormally shaped RBCs immediately after shock and during the postresuscitation period. In PES and ES female rats, RBC shape distribution did not significantly change after T/HS. Plasma malonyldialdehyde levels at 6 hours post-T/HS were higher in the male rats than in PES female rats.
  
  
  CONCLUSIONS
  These data show that high levels of estrogen in female rats are protective against shock-induced RBC damage and suggest that this effect is associated with a decrease in lipid peroxidation.
authors.affiliation: Department of Surgery, UMD-New Jersey Medical School, Newark, NJ 07103, USA. george.machiedo@med.va.gov
authors.forename: George W
authors.initials: GW
authors.lastname: Machiedo
authors.forename: Sergey
authors.initials: S
authors.lastname: Zaets
authors.forename: Tamara
authors.initials: T
authors.lastname: Berezina
authors.forename: Da-Zhong
authors.initials: DZ
authors.lastname: Xu
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Spolarics
authors.forename: Edwin A
authors.initials: EA
authors.lastname: Deitch
mesh_terms: D000818:Animals; D004907:Erythrocyte Deformability / Q000235:genetics*; D004971:Estrus; D005260:Female; D015227:Lipid Peroxidation; D008297:Male; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017207:Rats, Sprague-Dawley; D012737:Sex Factors; D012771:Shock, Hemorrhagic / Q000097:blood*; D014947:Wounds and Injuries / Q000097:blood*