Osteogenic effects of PTHrP (107-111) loaded in bioceramics in a model of bone regeneration after a cavitary defect in the femur of a rabbit

Summary Introduccion: Parathyroid hormone-related protein (PTHrP), which is abundant in bone tissue, is an important modulator of bone formation. It has been shown that PTHrP (107-111), called osteostatin, loaded into mesoporous ceramic material SBA-15 exerts osteogenic action in vitro. Objective: To confirm if this material and a functionalised version of the same material (C8-SBA-15) promote bone regeneration in a model of a cavitary defect in a rabbit femur. Materials and methods: Histological, immunohistochemical and computerised microtomography (µCT) studies were carried out in order to achieve the aims of the study. Results: After the implantation of the biomaterials no significant levels of inflammation or bone resorption were observed (at 4 and 8 weeks). At 8 weeks the bioceramics not loaded with osteostatin were found to be separated from the bone medulla by a fibrous capsule which diminished significantly in the presence of the peptide. An increase was observed (using µCT) in bone neo-formation at different distances from the biomaterials, principally in those loaded with the osteostatin. These results were also confirmed by immunohistochemistry of osteoblast markers. Conclusion: Our results suggest that the use of these osteostatin-loaded bioceramics are a good strategy for accelerating bone regeneration.