Macrophages phenotype identification during repair of bone defect's reconstructed with different biomaterials and their influence on healing process and on the quality of newly formed bone

Abstract

Knowledge about the action of immune system in the recognition of biomaterials has been extremely helpful when it comes about the understanding on host response and biomaterials' fate in human body. The same can be said about bone substitutes that due to variety of their physicochemical aspects allow different responses in relation to the quality and quantity of cell population, biomaterials' persistence, quantity and quality of the newly formed bone, and the presence of other tissues. Considering biomaterials' cells recognition, attention is called to macrophages, which morphological and functional plasticity permit that they determine how the organism will react in the presence of a specific biomaterial. In this way, this study aims to identify the phenotype of the macrophages that participate of bone healing process of rat's calvaria, using different bone substitutes, in order to evaluate their influence on bone repair and on the quality of the newly formed bone tissue. Eighty male Wistar rats will undergo surgical procedure for the confectioning of a 5-mm diameter bone defect in their right parietal bone. The animals will be divided into four groups (n=20 each), according the the filling material: Group C - Control, particulate intramembranous autogenous bone graft, Group BO - particulate deproteinized bovine bone, Group BC - particulate biphasic calcium phosphate with HA/TCP (60/40), Group BS - particulate bioactive glass ceramic. After 3, 7, 21, and 45 days, the animals will be euthanized for specimens' removal to be prepared for histological and polarized microscopy, immunohistochemical, immunofluorescence and computed microtomography (microCT) analysis. (AU)