Modulation of Integrin Expression on Rat Bone Marrow Cells by Substrates with Different Surface Characteristics

Abstract

Biomaterials have been shown to be able to influence the growth and differentiation of osteogenic cells cultured on the surface. Although the precise mechanisms by which the materials influence osteogenic cells are unclear, it is possible that the materials manipulate the expression of integrins by the cells. We therefore studied the expression of a number of integrins by rat bone marrow (RBM) cells, after culture on culture polystyrene, on machined and grit-blasted titanium, and on calcium phosphate-coated titanium. Integrin expression was studied by FACS analysis. We found a large variation in the expression of integrins by cells in replicate experiments. After culture on polystyrene for 7 days, cells expressed α1, α2, α3, α5, α6, β1, and β3, although some of the subunits were expressed only occasionally. The cells did not express the α4 subunit. After culture of RBM cells for 8 days on coated and noncoated titanium substrates, cells always expressed α3, α5, α6, and β1. The α1 and β3 subunits were only expressed in some of the experiments. Frequently, the expression of α5, α6, and β1 was higher on the coated than on the noncoated titanium substrates. Based on our results, we conclude that the studied materials are capable of influencing the expression of integrins by RBM cells cultured on relevant implant materials.