Efeito da terapia laser de baixa intensidade associada a enxerto ósseo liofilizado bovino no processo de reparação óssea – estudo conduzido em ratos

Abstract

The aim of this study was to assess histologically and histometrically the effect of the association of low level laser therapy and organic bovine bone graft Gen-ox® on the repair of bone defects on the femur of Wistar albinus rats during the early stages of bone repair. Fifty rats were divided in three groups of 25 femurs each, as follow: group I (control), group II (Gen-ox®) and group III (Gen-ox® and LLLT). The animals on group III were irradiated transcutaneously at four points around the defect every 48 h. The first irradiation was immediately after the procedure. At each point a dose of 5 J/cm2 was given (Ø~0.4, 70 mW) and the total dose per session was 20 J/cm2. The animals were killed by an overdose of general anesthetic 1, 3, 5, 7 e 15 days after surgery. For histological assessment at days 1, 3 and 5, the specimens were routinely processed by embedding in paraffin, serially cut and stained with H&E and analyzed under light microscopy. For histomorphometric assessment, the mean volume of the newly formed bone was estimated by digital capture (Axiovision®) of three areas in each specimen at days 5, 7 and 15. Statistical analyses of the mean values were performed using analysis of variance (ANOVA), with p ≤ 0,05 and post hoc LSD test. The results showed that the specimens of group III presented a higher concentration of collagen fibers, intense reaction in the periosteum cell opposite to the defect at days 3 and 5 as compared to groups I and II. It was observed an increased bone formation in group III in all experimental periods of time. These results showed statistical significance at days 5 and 15 as compared to groups I and II. Within the parameters of this study, it was concluded that LLLT associated to organic bovine bone graft had a positive effect on the repair of bone defects of rats.