title: Helium-neon laser reduces the inflammatory process of arthritis.
abstract: OBJECTIVE
  A histological study of the anti-inflammatory effect of helium-neon laser in models of arthropathies induced by hydroxyapatite and calcium pyrophosphate in rats.
  
  
  BACKGROUND
  Crystal deposition diseases are inflammatory pathologies induced by cellular reaction to the deposit of crystals in the joints.
  
  
  METHODS
  Fifty-six Suquia strain rats were distributed in seven groups. Two mg of each crystal diluted in 0.05 ml physiologic solution were injected six times in each back limb joint, during two weeks on alternate days. Eight J/cm(2) were applied daily to the crystal-injected joints on five consecutive days. The joints were cut and put in 10% formaldehyde, stained with hematoxylin-eosin and observed by light microscopy. The percentage of area with inflammatory infiltrates was determined in five optical microscopy photographs (100X) for each group and analyzed using the Axionvision 4.6 program. A Pearson's Chi Squared test was applied, with significance level set at p < 0.05.
  
  
  RESULTS
  Both crystals produced an inflammatory process in the osteoarticular structures, consisting of predominantly mononuclear infiltration, fibrosis, and granulomas of foreign body-type giant cells containing phagocytosed remains of crystals. In the arthritic joints treated with laser, a marked decrease (p < 0.0001) was found in the percentage of area with inflammatory infiltrates, although the granulomas remained in a less ostensible form, with adipose tissue cells, fibrosis bands with light residual inflammation, and an absence of or very few crystals. Laser alone or physiologic solution injection did not produce histological changes.
  
  
  CONCLUSIONS
  Helium-neon laser reduced the intensity of the inflammatory process in the arthritis model induced by hydroxyapatite and calcium pyrophosphate crystals.
authors.affiliation: Cátedra de Física Biomédica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
authors.forename: Claudia Reinoso
authors.initials: CR
authors.lastname: Rubio
authors.forename: David
authors.initials: D
authors.lastname: Cremonezzi
authors.forename: Monica
authors.initials: M
authors.lastname: Moya
authors.forename: Fernando
authors.initials: F
authors.lastname: Soriano
authors.forename: Jose
authors.initials: J
authors.lastname: Palma
authors.forename: Vilma
authors.initials: V
authors.lastname: Campana
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000139:chemically induced / Q000532:radiotherapy*; D002131:Calcium Pyrophosphate; D016009:Chi-Square Distribution; D004195:Disease Models, Animal; D017886:Durapatite; D054020:Lasers, Gas; D028022:Low-Level Light Therapy / Q000379:methods*; D051381:Rats
chemical_list: D017886:Durapatite; D002131:Calcium Pyrophosphate