SURFACE-ROUGHNESS MODULATES THE LOCAL PRODUCTION OF GROWTH-FACTORS AND CYTOKINES BY OSTEOBLAST-LIKE MG-63 CELLS

Titanium (Ti) surface roughness affects proliferation, differentiation , and matrix production of MG-63 osteoblast-like cells. Cytokines and growth factors produced in the milieu surrounding an implant may also be influenced by its surface, thereby modulating the healing process. This study examined the effect of surface roughness on the production of two factors known to have potent effects on bone, prostaglandin E(2 ) (PGE(2)) and transforming growth factor beta(1) (TGF-beta(1)). MG-63 cells were cultured on Ti disks of varying roughness. The surfaces we re ranked from smoothest to roughest: electropolished (EP), pretreated with hydrofluoric acid-nitric acid (PT), fine sand-blasted, etched wi th HCl and H2SO4, and washed (EA), coarse sand-blasted, etched with HC l and H2SO4, and washed (CA), and Ti plasma-sprayed (TPS). Cells were cultured in 24-well polystyrene (plastic) dishes as controls and to de termine when confluence was achieved, Media were collected and cell nu mber determined 24 h postconfluence. PGE(2) and TGF-beta(1) levels in the conditioned media were determined using commercial radioimmunoassa y and enzyme-linked immunosorbent assay kits, respectively. There was an inverse relationship between cell number and Ti surface roughness. Total PGE(2) content in the media of cultures grown on the three rough est surfaces (FA, CA, and TPS) was significantly increased 1.5-4.0 tim es over that found in media of cultures grown on plastic or smooth sur faces. When PGE(2) production was expressed per cell number, CA and TP S cultures exhibited six- to eightfold increases compared to cultures on plastic and smooth surfaces. There was a direct relationship betwee n TGF-beta(1) production and surface roughness, both in terms of total TGF-beta(1) per culture and when normalized for cell number. TGF-beta (1) production on rough surfaces (CA and TPS) was three to five times higher than on plastic. These studies indicate that substrate surface roughness affects cytokine and growth factor production by MG-63 cells , suggesting that surface roughness may modulate the activity of cells interacting with an implant, and thereby affect tissue healing and im plant success. (C) 1996 John Wiley & Sons, Inc.