Effects of hyperbaric oxygen therapy and platelet-rich plasma on femur fracture repair in rabbits

Abstract

Although in normal conditions most fractures do not present consolidation problems, in some situations bone tissue is knowingly poorly vascularized and does not conveniently respond to treatment. So, new techniques helping bone repair and stimulating fractures consolidation are of paramount importance. The use of growth factors is based on the possibility of promoting neovascularization of the bone callus, thus favoring bone repair. Hyperbaric oxygen therapy, on the other hand, aims at stimulating angiogenesis and, as a consequence, the consolidation process. OBJECTIVES: This study aims at evolutionarily studying the repair of bone fracture experimentally produced in rabbits femur, by the action of autologous platelet-derived growth factor, and of hyperbaric oxygenation, with the help of serial X-Rays, in addition to histological follow-up evaluation through bone callus study and morphometry. METHODS: This study shall involve 128 New Zealand male rabbits, mean weight of 3 kg, which shall be distributed in 4 groups: 1.Control Group (CG): animals submitted to osteotomy and osteosynthesis; 2.Autologous platelet-derived growth factor group (GFG): animals submitted to osteotomy,osteosynthesis and application of autologous platelet-derived growth factor; 3.Autologous platelet-derived growth factor and Hyperbaric Oxygen Therapy Group (GFG-HBO): animals submitted to osteotomy, osteosynthesis, application of autologous platelet-derived growth factor, and nine daily consecutive hyperbaric oxygenation sessions; 4.Hyperbaric Oxygen Therapy Group (HBOG): animals submitted to osteotomy, osteosynthesis and nine daily consecutive hyperbaric oxygenation sessions. Each group shall be divided in four sub-groups, with eight animals each, according to the pre-established euthanasia period: two, four, six and eight postoperative weeks. EXPECTED RESULTS: According to the literature, growth factors may improve bone formation and mineralization, induce undifferentiated mesenchymal cells to differentiate into osteoblasts, trigger the release of several other growth factors, decrease bone absorption, stimulate angiogenesis and produce collagen by fibroblasts activation. HBO is known for leading to angiogenesis and, as a consequence, to osteoblasts stimulation, accelerating bone callus development. So, we expect to show that the application of Platelet-Rich Plasma (PRP) associated to HBO, may lead to faster consolidation, with lower consolidation delay and pseudoarthrosis index, allowing for a faster recovery of patients. (AU)