Effects of 830-nm Laser, Used in Two Doses, on Biomechanical Properties of Osteopenic Rat Femora

Abstract

The aim of this study was to investigate the effects of photoradiation--infrared at 830 nm--used in two doses, on femora of osteopenic rats. Osteoporosis has recently been recognized as a major public health problem. Based on stimulatory effects of photoradiation on the proliferation of bone cells, we hypothesized that photoradiation would be efficient in improving bone mass in osteopenic rats. Sixty female animals, divided into six groups, were used: sham-operated control (SC), osteopenic control (OC), sham-operated irradiated with the dose of 120 J/cm(2) (I120), osteopenic irradiated with the dose of 120 J/cm(2) (O120), sham-operated irradiated with the dose of 60 J/cm(2) (I60), and osteopenic irradiated with the dose of 60 J/cm(2) (O60) Animals were 90 days old when operated. Laser irradiation was initiated 8 weeks after operation, and it was performed 3 times a week for 2 months. Femora were submitted to a biomechanical test and to a physical properties evaluation. Maximal load of O120 did not show any difference when compared with SC and I120, but it was higher than the O60 group. Wet weight, dry weight, and bone volume of O60 and O120 did not show any difference when compared with SC. The results of the present study indicate that photoradiation had stimulatory effects on femora of osteopenic rats, mainly at the dose of 120 J/cm.(2) However, further studies are needed to investigate the effects of different parameters, wavelengths, and sessions of applications on ovariectomized rats.