Effect of surface roughness on proliferation and alkaline phosphatase expression of rat calvarial cells cultured on polystyrene

Rough-surfaced substrates made by a variety of methods have been shown to i nfluence osteoblast proliferation and differentiation. The purpose of this study is to confirm the role of surface roughness in promoting osteoblastic differentiation using tissue culture polystyrene as substrate, by excludin g factors other than roughness. Immature osteogenic cells derived from feta l rat calvariae were cultured on the plastic cover strips having varied deg rees of roughness created by treatment with four kinds of grinding paper of different particle sizes. The proliferation and gene expression of alkalin e phosphatase (ALP) and osteocalcin of the calvarial cells increased on the rough-surfaced cover strips. These levels increased in response to the inc rease in the degree of surface roughness up to 0.8 mu m of average roughnes s and then decreased to the level observed for the smooth surface. These re sults demonstrate that the surface roughness itself caused increases in ost eoblastic proliferation and differentiation in cell cultures. (C) 1999 by E lsevier Science Inc. All rights reserved.