Evaluation of the inflammatory responses to sol-gel coatings with distinct biocompatibility levels

The immune system plays a crucial role in determining the implantation outcome, and macrophages are in the frontline of the inflammatory processes. Further, cellular oxidative stress resulting from the material recognition can influence how cell responses develop. Considering this, the aim of this study was to study oxidative stress and macrophages phenotypes in response to sol-gel materials with distinct in vivo outcomes. Four materials were selected (70M30T and 35M35G30T, with high biocompatibility, and 50M50G and 50V50G, with low biocompatibility). Gene expression, immunocytochemistry and cytokine secretion profiles for M1 and M2 markers were determined. Moreover, oxidative stress markers were studied. Immunocytochemistry and ELISA showed that 50M50G and 50V50G lead to a higher differentiation to M1 phenotype, while 70M30T and 35M35G30T promoted M2 differentiation. In oxidative stress, no differences were found. These results show that the balance between M1 and M2, more than individual quantification of each phenotype, determines a biomaterial outcome.