title: Different power settings of LLLT on the repair of the calcaneal tendon.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effect of an 830-nm GaAlAs diode laser operating at output powers of 40, 60, 80, and 100 mW and energy density of 30 J/cm(2) on the repair of partial calcaneal tendon ruptures in rats.
  
  
  METHODS
  A partial tendon rupture was induced in all animals, which were treated with laser irradiation for 5 consecutive days. Six days after injury, the injured tendons were removed and examined by polarized light microscopy. Collagen fiber organization was evaluated by birefringence measurements, and collagen content was determined by Picrosirius Red staining.
  
  
  RESULTS
  It was observed that the higher the output power (60-100 mW) the greater the amount of type III collagen (p<0.01). The amount of type I collagen was significantly greater (p=0.05) in the 80 mW group than in the control group (sham stimulation). A non-statistically significant improvement in the realignment of collagen fibers was observed in the irradiated groups.
  
  
  CONCLUSIONS
  Low-level laser therapy resulted in significantly greater amounts of type III collagen (output powers of 60 mW or more) and type I collagen (output power of 80 mW), however, no significant differences between groups were found in the realignment of collagen fibers.
authors.affiliation: Department of Plastic Surgery, Universidade Federal de São Paulo, Rua Napoleão de Barros 715, São Paulo, Brazil. marcoain@gmail.com
authors.forename: Marco Aurelio Invaldi
authors.initials: MA
authors.lastname: Neves
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Pinfildi
authors.forename: Viviane Timm
authors.initials: VT
authors.lastname: Wood
authors.forename: Rafael Corrêa
authors.initials: RC
authors.lastname: Gobbato
authors.forename: Fabio Mendes
authors.initials: FM
authors.lastname: da Silva
authors.forename: Nivaldo Antônio
authors.initials: NA
authors.lastname: Parizotto
authors.forename: Bernardo
authors.initials: B
authors.lastname: Hochman
authors.forename: Lydia Masako
authors.initials: LM
authors.lastname: Ferreira
mesh_terms: D000125:Achilles Tendon / Q000293:injuries* / Q000528:radiation effects*; D000704:Analysis of Variance; D000818:Animals; D003094:Collagen / Q000378:metabolism; D004195:Disease Models, Animal; D054023:Lasers, Semiconductor; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012421:Rupture; D013708:Tendon Injuries / Q000532:radiotherapy*
chemical_list: D003094:Collagen