Effects of Repeated He-Ne Laser-based Photobiomodulation on Bone Healing in a Rat Femoral Defect Model

This study investigated the effects of repeated helium-neon (He-Ne) laser-based photobiomodulation therapy (PBMT) on bone healing in a rat femoral defect model. Bilateral 0.8-mm monocortical bone defects were created in the distal femurs of Sprague-Dawley rats, with one side receiving repeated He-Ne laser irradiation (632.8 nm, 25 mW, 7.5 J) and the other serving as a control. Histological and image-based bone density analyses were performed on postoperative days 7 and 14. The irradiated group exhibited enhanced trabecular bone formation and significantly higher bone density on day 7, particularly in the marrow region. However, bone density decreased in this group by day 14, suggesting progression to bone remodeling. These findings indicate that PBMT using He-Ne laser promotes early-stage bone formation and may accelerate the bone healing process, thus supporting the therapeutic potential of PBMT for bone regeneration.