Effect of a laser irradiation on the vascularisation of safety and X-ray radiated bone.

ABSTRACT

Thermal preconditioning induces a cytoprotective effect and promotes tissue recovering. Laser is an appropriated method to generate a controlled and reproducible heating. Bone healing, a crucial challenge in medicine, is affected by X-ray radiation which induces a chronic antiangiogenic effect. So, this study aims to investigate the role of laser preconditioning on the vascularisation of bone after X-ray radiation. An optical bone chamber allowed the study of the vascularization process. The vascular density (VD) was determined using image processing. A longitudinal study was performed on 20 rabbits divided in four groups #1 control group (n=5); #2 laser irradiation alone (diode laser 810nm, fluence= 48J/cm2) (n=5). #3 X-ray radiation (18.75Gy) alone (n=5), #4 laser preconditioning 24 hours before a X-ray radiation (n=5). VD remained stable during 12-week follow up for groups #1 and #2. X-ray radiation lead to an important decrease of the superficial bone vascularization in group #3. The decrease of the vascularization was limited in group #4 highlighting a different evolution between group #3 and #4. Those results were confirmed by histological analysis. Our preliminary findings show that laser preconditioning preserves vascularization in X-ray radiated bone site, outlining a novel approach for the bone healing in which the vascular supply has been injured.