Low-level laser therapy enhances the expression of osteogenic factors during bone repair in rats

Abstract

The aim of this study was to evaluate the effects of low-level laser therapy (LLLT) on bone formation, immunoexpression of osteogenic factors, and biomechanical properties in a tibial bone defect model in rats. Sixty male Wistar rats were distributed into bone defect control group (CG) and laser irradiated group (LG). Animals were euthanized on days 15, 30, and 45 post-injury. The histological and morphometric analysis showed that the treated animals presented no inflammatory infiltrate and a better tissue organization at 15 and 30 days postsurgery. Also, a higher amount of newly formed bone was observed at 15 days postsurgery. No statistically significant difference was observed in cyclooxygenase-2 immunoexpression among the groups at 15, 30, and 45 days in the immunohistochemical analysis. Considering RUNX-2, the immunoexpression was statistically higher in the LG compared to the CG at 45 days. BMP-9 immunoexpression was significantly higher in the LG in comparison to CG at day 30. However, there was no expressivity for this immunomarker, both in the CG and LG, at the day 45 postsurgery. No statistically significant difference was observed in the receptor activator of nuclear factor kappa-B ligand immunoexpression among the groups in all periods evaluated. No statistically significant difference among the groups was observed in the maximal load in any period of time. Our findings indicate that laser therapy improved bone healing by accelerating the development of newly formed bone and activating the osteogenic factors on tibial defects, but the biomechanical properties in LG were not improved.

Improvement of bone repair in diabetic rats subjected to ƛ780 nm low-level laser therapy

“…Hence, LLLT is able to improve bone formation by direct stimulation of osteoblastic metabolism, with consequent increase of protein synthesis (particularly collagen) and cell levels of adenosine triphosphate 21 . LLLT also seems to increase the expression of Runx-2 gene, a transcription factor involved in osteoblast differentiation of pluripotent mesenchymal cells 8,25 . Furthermore, LLLT promotes important changes in chemical mediators directly involved on the repair, such as reduction of cyclooxygenase-2 expression (COX-2), reducing the severity of the inflammatory response, and increase of VEGF expression, a growth factor crucial for the formation of granulation reaction 26 .…”

The efficacy of low-level 940 nm laser therapy with different energy intensities on bone healing

“…20,24 Conversely, no significant effect of LLLT has been reported in cells. 30 The effect of LLLT has been investigated in bone tissue with wavelengths ranging from 670 to 1064 nm.…”

“…19,20,21 Among all these methods, LLLT outshines other modalities due to the advantage of being non-invasive and the ease of application in clinical use. However, there is still no standard protocol for LLLT application to promote bone healing in the literature.…”

The Effect of Low Intensity Pulsed Ultrasound Therapy on Osseointegration and Marginal Bone Loss Around Dental Implants

“…Continuous bone resorption aff ects function and aesthetic. There are several ways to restore and regenerate bone such as advocating bone grafting procedures, addition of growth proteins and application of low level laser therapy that have produced variable clinical results [7][8][9] . Many for dental implant therapy.…”