title: Effect of hypertonic saline on leukocyte activity after spinal cord injury.
abstract: METHODS
  The effect of intravenous administration of hypertonic saline on leukocyte adhesion after compression injury of the spinal cord was evaluated.
  
  
  OBJECTIVE
  To investigate changes in leukocyte adhesion after spinal cord injury and to evaluate the effect of hypertonic saline on this process.
  
  
  BACKGROUND
  Leukocytes have been thought to exacerbate tissue injury after ischemia-reperfusion. Downregulating and reducing the number of circulating leukocytes has attenuated tissue damage in various models of cerebral ischemia. Recently, investigators have reported that leukocytes exacerbate injury in the spinal cord after trauma. Other recent findings have indicated that hypertonic saline may play a role in decreasing leukocyte adhesion and activation.
  
  
  METHODS
  Sprague-Dawley rats were anesthetized, and a C3-C5 laminectomy was performed. Injury was caused by 35 g of compression applied to the cord for 10 minutes. Animals were divided into three groups: sham treated, untreated, and treated. The treated animals received 7.5% hypertonic saline (5 mL/kg, intravenously) 5 minutes after the injury. Sticking leukocytes and shear rate were measured using fluorescence microscopy.
  
  
  RESULTS
  Administration of 7.5% hypertonic saline after injury significantly decreased the number of sticking leukocytes in the venules and arterioles. Shear rate was unchanged between the groups.
  
  
  CONCLUSIONS
  The results show that an increase in leukocyte adhesion after a compressive injury is attenuated by the administration of 7.5% hypertonic saline. The decrease in adhesion cannot be attributed to changes in the shearing forces, because no significant change was observed in the shear rate. Hypertonic saline may interfere with leukocytes directly by interfering with their ability to swell and thus may prevent activation.
authors.affiliation: Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Spera
authors.forename: K E
authors.initials: KE
authors.lastname: Arfors
authors.forename: U S
authors.initials: US
authors.lastname: Vasthare
authors.forename: R F
authors.initials: RF
authors.lastname: Tuma
authors.forename: W F
authors.initials: WF
authors.lastname: Young
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D007962:Leukocytes / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012462:Saline Solution, Hypertonic / Q000627:therapeutic use*; D013117:Spinal Cord Compression / Q000097:blood / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors
chemical_list: D012462:Saline Solution, Hypertonic