title: Effects of 830-nm laser light on preventing bone loss after ovariectomy.
abstract: OBJECTIVE
  The aim of this study was to investigate the effects of low-level laser therapy (LLLT; infrared, 830 nm) on the bone properties and bone strength of rat femora after ovariectomy (OVX).
  
  
  BACKGROUND
  Osteoporosis affects 30% of postmenopausal women, and it has been recognized as a major public health problem. Based on the stimulatory effects of LLLT on proliferation of bone cells, we hypothesized that LLLT would be efficient in preventing bone mass loss in OVX rats.
  
  
  METHODS
  Forty female rats were divided into four groups: sham-operated control (SC), OVX control (OC), sham-operated irradiated at a dose of 120 J/cm(2) (I120), and OVX irradiated at a dose of 120 J/cm(2) (O120). Animals were operated at the age of 90 days. Laser irradiation was initiated 1 day after the operation and was performed three times a week, for 2 months. Femora were submitted to a biomechanical test and a physical properties evaluation.
  
  
  RESULTS
  Maximal load of O120 was higher than in control groups. Wet weight, dry weight, and bone volume of O120 did not show any difference when compared with SC.
  
  
  CONCLUSIONS
  The results of the present study indicate that LLLT was able to prevent bone loss after OVX in rats. However, further studies are needed to investigate the effects of different parameters, wavelengths, and sessions of applications on OVX rats.
authors.affiliation: Department of Physiotherapy, Federal University of São Carlos, São Carlos, Brazil.
authors.forename: Ana Claudia Muniz
authors.initials: AC
authors.lastname: Renno
authors.forename: Fernanda Mendes
authors.initials: FM
authors.lastname: de Moura
authors.forename: Nádia Slemer Andrade
authors.initials: NS
authors.lastname: dos Santos
authors.forename: Renata Passarelli
authors.initials: RP
authors.lastname: Tirico
authors.forename: Paulo Sérgio
authors.initials: PS
authors.lastname: Bossini
authors.forename: Nivaldo Antonio
authors.initials: NA
authors.lastname: Parizotto
mesh_terms: D000818:Animals; D015519:Bone Density / Q000528:radiation effects; D005260:Female; D005269:Femur / Q000528:radiation effects; D007834:Lasers; D009929:Organ Size / Q000528:radiation effects; D010024:Osteoporosis / Q000517:prevention & control*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar