Evaluation of the Effects of Photobiomodulation on Biomechanical Properties and Hounsfield Unit of Partial Osteotomy Healing in an Experimental Rat Model of Type I Diabetes and Osteoporosis

Abstract

Pulsed wave (PW) lasers exhibit biostimulatory effects on fractures in healthy and diabetic animals. This study aims to assess the effects of photobiomodulation on bone strength and Hounsfield unit (HU) for repair of a bone defect in an experimental rat model of type I diabetes mellitus (TIDM) and osteoporosis (OP). We divided 30 female rats into six groups of n = 5 per group: (1) ovariectomy (OVX) control, (2) OVX + PW laser and no TIDM, (3) OVX control + TIDM, (4) OVX + TIDM + PW laser, (5) OVX + TIDM + alendronate, and (6) OVX + TIDM + PW laser + alendronate. TIDM was induced in rats by streptozotocin (STZ). A partial osteotomy was made in the right tibia of each rat. We used an infrared laser (890 nm, 80 Hz, 1.5 J/cm2) 3 times per week. At 30 days after surgery, the callus areas within the rats' tibias were submitted to computed tomography scanning followed by the three-point bending test. The PW laser + alendronate group had significantly increased HU and biomechanical properties of repairing bone defect in STZ + OVX rats compared with the control groups. Combined treatment of PW laser and alendronate significantly enhanced bone repair in an experimental model rat of TIDM and OP.