Blood clot formed on rough titanium surface induces early cell recruitment

The initial contact of blood with biomaterials and subsequent recruitment of inflammatory and marrow-derived stromal cells are among the first phases of bone regeneration. The aim of this study was to investigate the migratory potential of mesenchymal stem cells by treating rat bone marrow mesenchymal stromal cells (rBMSCs) with the extract of the blood clot formed on implant surfaces.Cell attachment and morphology on the blood clot was observed using scanning electron microscopy. The cell metabolism was reflected by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, and the cell proliferation was assessed by the CyQuant(®) assay based on DNA content. Cytokine profiles in the incubation medium derived from different blood-titanium surface were detected using the rat cytokine antibody array. Scratch wound assay and transwell migration assay were performed to determine the effect of blood-implant conditioned medium on cell migration and movement.No significant difference was found in cell attachment and morphology on the blood clot formed on smooth and rough surfaces. Increased rBMSC proliferation was induced by the blood clot on rough surfaces. Comparison of cytokine secretion showed a significant increase of CINC-2α, IL-2, L-selectin, MCP-1, prolactin AA and VEGF levels in the elution of blood clot formed on rough titanium surfaces, which led to significantly improved mobility and wound healing ability of rBMSCs.Rough titanium surfaces could influence the blood clot formation and properties, which will induce cell recruitment and stimulate wound healing.