Rat subcutaneous tissue response to macrogranular porous anorganic bovine bone graft

The ideal bone graft must present biocompatibility, osteoconductive and osteoinductive properties, resistance and plasticity. Xenogenic grafts of bovine cancellous bone origin are particularly interesting due to their biologically designed porous structure that enhance both cellular and vascular invasion. The purpose of this study was to evaluate the tissue response induced by bovine macrogranular porous anorganic bone implanted in rat subcutaneous tissue. Forty rats were assigned to 2 groups, as follows: the control group received empty collagen capsules and the test group received subcutaneous implants of the test material. Samples were collected after 10, 20, 30 and 60 days and processed histologically. Histological analysis showed at 10 days a granulomatous inflammatory infiltrate, rich in multinucleated giant cells and free of lymphocytes or plasma cells, similarly to mineralized allograft implanted in rat subcutaneous. In later periods, there was a significant decrease in the inflammatory infiltrate and an increase in fibrosis around graft particles. In conclusion, the test material induced a foreign body-type granuloma with subsequent fibrosis around the graft particles implanted in rat subcutaneous and did not elicit any immune response, thus being considered biocompatible.