Low‐level laser therapy (780 nm) combined with collagen sponge scaffold promotes repair of rat cranial critical‐size defects and increases TGF‐β, FGF‐2, OPG/RANK and osteocalcin expression

Abstract

The aim of this study was to evaluate the effect of collagen sponge scaffold (CSS) implantation associated with low-level laser therapy (LLLT) on repairing bone defects. A single 5-mm cranial defect was surgically created in forty Wistar rats, which then received one of the following four interventions (n = 10 per group): no treatment (G0); bone defect implanted with collagen sponge scaffold (CSS) alone (G1); defect treated with low-level laser therapy (LLLT) (wavelength 780 nm; total energy density 120 J/cm ; power 50 mW) alone (G2); and CSS associated with LLLT treatment (G3). After surgery, animals in each group were euthanized at 21 days and 30 days (n = 5 per euthanasia time group). Bone formation was monitored by X-ray imaging analysis. Biopsies were collected and processed for histological analysis and immunohistochemical evaluation of transforming growth factor-beta (TGF-β), fibroblast growth factor-2 (FGF-2), osteoprotegerin (OPG) and receptor activator of nuclear factor ƙ (RANK). Osteocalcin (OCN) was detected by immunofluorescence analysis. Compared to the G0 group, defects in the 30-day G3 group exhibited increased bone formation, both by increase in radiopaque areas (P < 0.01) and by histomorphometric analysis (P < 0.001). The histopathological analysis showed a decreased number of inflammatory cells (P < 0.001). The combined CCS + LLLT (G3) treatment also resulted in the most intense immunostaining for OPG, RANK, FGF-2 and TGF-β, and the most intense and diffuse OCN immunofluorescent labelling at 30 days postsurgery (G3 vs. G0 group, P < 0.05). Therefore, the use of CCS associated with LLLT could offer a synergistic advantage in improving the healing of bone fractures.

Fibrin Sealant Derived from Human Plasma as a Scaffold for Bone Grafts Associated with Photobiomodulation Therapy

“…The defects filled with fibrin and xenograft (FSB and FSB PBMT ) sealers showed intense angiogenesis as early as 14 days, as well as the presence of reactional tissue at 42 days of resolution [36]. The tissue reaction observed in these groups did not trigger a foreign body type granulomatous reaction, which suggests that the grafts used were biocompatible [26,37,38] and the biological response was consistent with the inflammatory process after implantation of the biomaterial [14,35,39,40,41,42,43].…”

“…Other attempts have been studied to minimise the time of bone healing and to reduce the chance of possible complications arising from the abnormal regeneration process. Among them, low-intensity pulsed ultrasound [12] and laser photobiomodulation therapy have been highlighted by their satisfactory effects on bone metabolism and repair, due to their possible osteogenic effect [13,14].…”

Fatores de crescimento e síntese de proteínas na resposta celular após aplicação do laser de baixa intensidade

“…Although through different methodologies and with different cell lines, in general, PBM upregulates FGF-2 synthesis [19,20,36,37], similarly to the result of this study.…”

Low power laser irradiation and human adipose-derived stem cell treatments promote bone regeneration of critical-sized calvarial defects in rats

“…Other studies have also demonstrated that LPLI affects osteogenesis and bone repair in comparative animal models [23][24][25][26][27][28]. LPLI therapies also induce alkaline phosphatase activity and increase osteocalcin gene expression, thus contributing to bone formation [29][30][31].…”