Efeito da oxigenação hiperbárica no reparo ósseo em fêmures de ratos submetidos à radiação ionizante.

Abstract

Hyperbaric oxygenation (OH) has shown positive effects on bone repair with increased osteogenesis and angiogenesis. The present study aimed to evaluate the effect of hyperbaric oxygenation on the repair of bone submitted to ionizing radiation, through histological and histomorphometric parameters and polarization microscopy. In this study 20 male rats were used, and the femurs of the animals were randomly assigned to four groups: Control, Radiotherapy, Hyperbaric Oxygenation and Radiotherapy with Hyperbaric Oxygenation. Initially, all the animals had radiotherapy in the left femur and, after 30 days, bone defects were created in both femurs. Subsequently, in 10 animals, hyperbaric oxygenation sessions were performed soon after the surgical procedure. The sacrifice period was 5 or 7 days after confection of the bone defect and initiation of therapy. After removal, the femurs were processed for inclusion in paraffin. For the histomorphometric analysis, the histological slides stained in HE were scanned and, with the Image-Pro Plus Version 4.5 program, the structures of interest were counted in a grid of 220 points. Bone neoformation was quantified in the Mallory trichrome slides in the region of the bone defect using the HL Image 2005 program. A qualitative analysis was performed for the evaluation of the collagen fibers in the slides stained in Picrosirius Red, analyzing the brightness intensity, marking predominance and lamellar organization. Data were analyzed with the Kolmogorov-Smirnov tests, unpaired t-test and ANOVA with Bonferroni correction. In general, the greatest differences occurred in the region of the bone defect, in detriment of the cortical bone. The results indicated that OH favors bone repair. However, in this experimental model OH was not sufficient to compensate for the damages caused by high doses of ionizing radiation in the bone.