Avaliação biológica de grânulos de ßTCP/HA e do seu potencial como carreador de células osteoprogenitoras humanas

Abstract

The aim of this study was the biological characterization of a biphasic ceramic (&#946;TCP: HA, 70:30). The cytocompatibility was tested with human osteoprogenitor cells (HOPC), after 24 hours of exposure to material extract (ISO 10993-5), using morphological and biochemical analysis (crystal violet). The HOPC adhesion to ceramic was evaluated after incubation for 14 days. The biocompatibility in subcutaneous tissue and repair of bone defects (&#1256;5mm) in rat calvaria (n = 20), of the material without cells (control) and with cells (HOPC), was evaluated concurrently on 15 and 45 days after the grafting using histology and histomorphometry. The material showed high cytocompatibility, with preservation of cell morphology and cell density similar to the estimated negative control. As showing by scanning electron microscopy, were present and adhered and sprawling HOPC on the surface of ceramic and indicative migration into the pores. At light microscopy, the subcutaneous tissue showed increased cellularity in the group with HOPC as compared to the pure ceramic, in both there was no polymorphonuclear leukocytes or necrosis and moderate presence of lymphocytes, macrophages and surrounding multinucleated giant cells (15 days), followed by maturation of tissue revascularization and compatible with the normal process of repair (45 days). The histopathologic findings of central skull defects after 15 days showed higher cellularity with HOPC together the ceramics than connective matrix in contact with the material without cells, in both there was mild presence of lymphocytes, macrophages and new blood vessels surrounding particles of the graft and after 45 days in the group with HOPC the ceramic was surrounded by loose connective tissue, blood vessels, few multinucleated giant cells and moderate new bone (6.64%), confirming the biomineralization process similar to the autograft (6.59%), which was higher than the group without cells (3.84%) and significantly different from the blood clot (2.23%, p <0.05), the latter with osteogenesis only at the edges of the defect such as the other groups. It can be concluded that the material tested is citocompatible, biocompatibile, osteoconductive and works as a carrier of cells to promote greater bone repair in vivo.