Laser stimulation on bone defect healing: an in vitro study.

The aim of this in vitro study was to evaluate whether low-power laser (LPL) stimulation can accelerate bone healing. Bone defects of a standard area were created in the distal epiphysis of 12 femora explanted from six rats, and they were cultured in BGJb medium for 21 days. Six defects were treated daily with Ga-Al-As, 780 nm LPL for 10 consecutive days (lased group, LG), while the remainder were sham-treated (control group, CG). Alkaline phosphatase/total protein (ALP/TP), calcium (Ca), and nitric oxide (NO) were tested on days 7, 14 and 21 to monitor the metabolism of cultured bone. The percentage of healing of the defect area was determined by histomorphometric analysis. After 21 days significant increases were observed in ALP/TP in LG versus CG (p<0.001), in NO in the LG versus CG ( p<0.0005) and in Ca in CG versus LG ( p<0.001). The healing rate of the defect area in the LG was higher than in the CG ( p=0.007). These in vitro results suggest that Ga-Al-As LPL treatment may play a positive role in bone defect healing.