The Effect of Titanium Surface Roughness on MG63 Oseteblast-Like Cell Differentiation and Response to 1,25-Dihydroxyvitamin D3

Surface roughness has been shown to affect cell differentiation and local factor production of MG63 osteoblast-like cells. The first specific aim of this study was to examine whether surface roughness alters the response of MG63 cells to circulating systemic hormones like 1,25-OH2D3 1,25. Unalloyed titanium Ti disks were pretreated with HFHNO3 PT and then machined and acid-etched MA. Ti disks were also sandblasted SB, sandblasted and acid-etched CA, or plasma-sprayed with Ti particles PS. The surfaces, from smoothest to roughest, were PT, MA, CA, SB, and PS. MG63 cells were cultured to confluence on standard tissue culture polystyrene plastic or the Ti surfaces and then treated for 24 hours with either 10exp -8M or 10exp -7M 1,25-OH2D3 or vehicle control. Cellular response was measured by assaying cell number, cell layer alkaline phosphatase specific activity, and the production of osteocalcin, latent transforming growth factor-beta LTGFbeta, and prostaglandin E2 PGE2. Alkaline phosphatase specific activity was affected by surface roughness as the surface became rougher, the cultures showed a significant increase in alkaline phosphatase specific activity. Addition of 1,25-OH2D3 to the cultures caused a dose-dependent stimulation of alkaline phosphatase specific activity which was synergistic with the effect caused by surface roughness alone. 1,25-OH2D3 also caused a synergistic increase in osteocalcin production, as well as local factor LTGFbeta and PGE2 production, on the rougher CA, SB and PS surfaces, but had no effect on the cultures grown on the smoother surfaces. The inhibitory effect of surface roughness on cell number was not affected by 1,25-OH2D3, except on the SB surface.