The Role Of Sterilization In The Effects Of Ti-MAO On Osteointegration Via Mediating Macrophage Polarization

[Objective] Fabricate plasma electrolyte oxidation coating on Ti surface and sterilize the samples with different sterilization methods.The following experiments is to evaluate the influence of Ti-MAO with different sterilization methods on attachment,morphology,polarization and inflammatory factors secretion of macrophages,and to detect the interaction between macrophages and b MSCs on Ti-MAO with different sterilization methods.[Methods] After being polished,pure titanium samples were fabricated with plasma electrolyte oxidation coating.The coated samples were sterilized with autoclaving,ethanol and UV irradiation,separately.The morphology,hydrophilicity,elementary composition and roughness of samples were measured.Mouse Macrophages were seeded on the samples.The adhesion and morphology of macrophages were observed,and the polarization and inflammation-related genes expression of macrophages were detected.A conditioned medium co-culture system model was constructed to detect the migration,proliferation and osteogenic differentiation of b MSCs.The feedback regulation of b MSCs in conditioned mediums against macrophage was also evaluated.[Results] After sterilized with different methods,the Ti-MAO samples showed no significant difference in morphology,roughness and element composition.Highest hydrophilicity and lowest macrophages adhesion were observed on UV irradiated samples.UV irradiated samples induced macrophages to spread as oval-like shape,whereas autoclaving and ethanol treated samples compelled the macrophage to stretch as spindlelike shape.UV irradiated sample surfaces induced M2 polarization of macrophages,which increased the secretion of growth factor and inhibited the secretion of inflammatory mediators.Autoclaving treated sample surfaces induced M1 polarization and enhanced the secretion of inflammatory factors.The ethanol treated sample surfaces stimulated the cells to secret less growth factor than UV irradiated ones and less inflammatory factors than autoclaving treated ones.The polarization of macrophages was induced directly by the surface of samples rather than the cytokines produced by themselves.The inflammatory genes expression was hardly detected in detached macrophages.Macrophage conditioned medium induced by UV irradiated surfaces could enhance the homing,proliferation and osteogenic differentiation of b MSCs.b MSCs inhibited osteoclast differentiation of macrophage in conditioned medium induced by UV irradiated surfaces,but enhanced in that induced by autoclaving treated surfaces..[Conclusions] Hydrophilicity of Ti-MAO could be influenced by different sterilization methods.The attachment and morphology of macrophages is affected by TiMAO surfaces with different sterilization methods.The polarization of macrophages and the secretion of inflammatory factors is directly controlled by Ti samples.Macrophages detached from the surface of Ti samples would lose their functions of inflammatory secretion.The interaction between macrophages and b MSCs through paracrine pathway is influenced by surfaces with different sterilization and plays a key role in the bone integration.