Evaluation of bone repair after radiotherapy by photobiomodulation-an animal experimental study

This research evaluated the effect of GaAlAs lasertherapy at the healing of surgical wounds produced in Wistar rat femurs a few days before the beginning of the radiotherapy. An orifice was artificially produced in the femur bone of the rats and they were submitted to an external radiotherapy with a radioactive source of cobalt in the dosage of 3000 cGys. The experimental group received additionally seven sessions of 780 nm, 40 mW, 100 or 5 J/cm(2) in four points around the surgical wound, at each 48 h, initiated at the day of surgery. These animals were then sacrificed at three and five weeks. The results were based on the clinical and histological analyses. Clinically, even though the rats had gained body mass within the time of the experiment (p < 0.05), those who has been submitted to the lasertherapy presented cutaneous inflammatory reactions. Regarding the histological findings, the number of osteocites (p < 0.0001) and Harvers channels (p < 0.0001) was significantly larger in the groups that had been radiated with laser during the experiment.