Efeito do laser de baixa potência e da oxigenação hiperbárica no reparo do osso submetido à radiação ionizante

Abstract

Bone healing is influenced by several factors such as the type of bone, severity of injury, presence of infection, fixation, age, health and nutrition. Some treatments, such as radiation, may also compromise bone tissue, limiting future possibilities of repair. When submitted to radiotherapy, bone tissue presents important changes in morphology and constitution. The effects of radiation on the bone, although well described, have not been fully clarified. Moreover, considering the large number of procedures involving this tissue, the understanding of these changes and ways to minimize them is of great importance in medicine and dentistry. The use of low-power laser therapy (LLT) modulates inflammation and cell proliferation, accelerating bone repair. The hyperbaric oxygen (HBO) has also been used to improve the repair of damaged tissues since it stimulates oxygenation, cell proliferation and neovascularization, with positive results in osteogenesis. Considering this context, this thesis aimed to investigate the effect of LLT and HBO on bone healing, in rats previously submitted or not to ionizing radiation. For this purpose, the experimental model of bone defect in the rat femur was used, and bone repair was evaluated by histological (qualitative) and morphometric (percentage of bone formation) parameters, bone densitometry, as well as expression of molecules related to osteogenesis and bone remodeling. The results indicated that LLT and HBO favor bone repair, but these effects, in general, were not enough to revert the damage caused by ionizing radiation in bone.