title: Low-level laser therapy (GaAs lambda = 904 nm) reduces inflammatory cell migration in mice with lipopolysaccharide-induced peritonitis.
abstract: OBJECTIVE
  This study was designed to study the effect of an infrared low-level laser (GaAs lambda = 904 nm, 4 mW) on inflammatory cell migration in lipopolysaccharide (LPS)-induced peritonitis in mice.
  
  
  BACKGROUND
  It has been suggested that red wavelengths of low-level laser therapy (LLLT) can exert anti-inflammatory effects, but little is known about the anti-inflammatory effects of infrared lasers. Peritonitis is a potentially life-threatening inflammatory condition that may be suitable for studying anti-inflammatory effects of infrared lasers.
  
  
  METHODS
  Sixty male mice were randomly divided into five groups, and one group was given an intraperitoneal sterile saline injection. In the remaining four groups, peritonitis was induced by an intraperitoneal LPS injection. Animals in three of the LPS groups were irradiated at a single point over the peritoneum with doses of 3 J/cm(2), 7.5 J/cm(2), and 15 J/cm(2), respectively. The fourth group injected with LPS was an LPS-control group.
  
  
  RESULTS
  At 6 hours after injection the groups irradiated with doses of 3 J/cm(2) and 7.5 J/cm(2) had a reduced number of neutrophil cells in the peritoneal cavity compared with the LPS-control group, and there were significant differences between the number of neutrophils in the peritoneal cavity between the LPS-control group and groups irradiated with doses of 3 J/cm(2) (-42%) and 7.5 J/cm(2) (-70%). In the group irradiated with 15 J/cm(2), neutrophil cell counts were lower than, but not significantly different from, LPS controls (-38%; p = 0.07). At 24 hours after injection, both neutrophil and total leukocyte cell counts were lower in all the irradiated groups than in the LPS controls. The 3-J/cm(2) exposure group showed the best results at 24 hours, with reductions of 77% in neutrophil and 49% in leukocyte counts.
  
  
  CONCLUSIONS
  Low-level laser therapy (904 nm) can reduce inflammatory cell migration in mice with LPS-induced peritonitis in a dose-dependent manner.
authors.affiliation: University Nove Julho, São Paulo, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Correa
authors.forename: Rodrigo Alvaro Brandão
authors.initials: RA
authors.lastname: Lopes Martins
authors.forename: Joao Carlos
authors.initials: JC
authors.lastname: Correa
authors.forename: Vegard V
authors.initials: VV
authors.lastname: Iversen
authors.forename: Jon
authors.initials: J
authors.lastname: Joenson
authors.forename: Jan M
authors.initials: JM
authors.lastname: Bjordal
mesh_terms: D000818:Animals; D002465:Cell Movement / Q000528:radiation effects*; D007249:Inflammation / Q000276:immunology; D007958:Leukocyte Count; D008070:Lipopolysaccharides / Q000276:immunology; D028022:Low-Level Light Therapy; D008297:Male; D051379:Mice; D010538:Peritonitis / Q000276:immunology*; D011897:Random Allocation