Os efeitos do Biosilicato® e do laser terapêutico de baixa potência no processo de consolidação em tíbias de ratos

Abstract

Fractures of delayed consolidation and fractures with non-union are commonly found in medical practice and are associated with high morbidity and mortality. Within this context, biochemical and biophysical resource have been studied in an attempt enhance bone healing. Among these may be highlighted the use of bioactive materials and low level laser therapy (LLLT). Several studies suggest that both resources are able to stimulate proliferation of osteoblasts and osteogenesis at the fracture site, promoting a greater deposition of bone mass and accelerating the process of consolidation. So the main purpose of the present work was to evaluate the effects of low-intensity laser (λ = 830nm), with fluencies of 60J/cm² and 120J/cm² and a bioactive ceramic, Biosilicato®, used alone or associated on bone consolidation of the tibial fractures in healthy rats. For the study 60 male Wistar rats were randomly divided in 6 groups: group bone defect control (GCF); group bone defect irradiated with LLLT, at 60 J/cm2 (GL60); group bone defect irradiated with LLLT, at 120 J/cm2 (GL120); group bone defect filled with Biosilicate® (GB); group bone defect filled with Biosilicate® , irradiated with LLLT, at 60 J/cm2 (GB60); and group bone defect filled with Biosilicate®, irradiated with LLLT, at 120 J/cm2 (GB120). A low-energy GaAlAs 830nm, CW, 100 mW, 60 and 120 J.cm² was used in this study. The rats were anesthetized by intraperitoneal injection of ketamine and xylazine 2% and a standardized 2.0-mm-diameter bone defect was created by using a motorized drill under copious irrigation with saline solution. Laser irradiation was initiated immediately after the surgery procedure and it was performed every 48 h for 14 days. After 14 day post-surgery, biomechanical analysis revealed no statistical differences between experimental groups. However, the morphological and morphometric analysis showed that the laser, in the two fluencies evaluated showed values statistically higher than control group and the Biosilicate®. Interestingly, the groups treated with Biosilicate® and laser, in two fluencies, showed statistically lower values of newly formed bone in the area of the defect even when compared with the control group. The scanning electron microscopy showed an intense presence of the biomaterial in bone defects of their animals. From the results obtained in this study, we concluded that the low-intensity laser was more effective in the process of bone repair when compared with biomaterial or the two resources associated.