Osteoblast cell death on methacrylate polymers involves apoptosis

The success of an implant depends on the implant-tissue interface. There ar e many causes of implant failure, one of which is tissue necrosis. The aim of this in vitro study was to determine whether cell death of primary human osteoblasts (implant site specific cells) occurred by apoptosis (a form of programmed cell death) on two methacrylate polymers. Cells were cultured o n poly(ethyl methacrylate)/ tetrahydrofurfuryl methacrylate and poly(methyl methacrylate in the form of 13-mm discs, in conditioned medium containing leachable monomer and in the presence of various concentrations of monomer itself in the culture medium. It was found that monomer and leached monomer caused apoptosis of human osteoblast cells in this system. Tetrahydrofurfu ryl methacrylate monomer was found to be more toxic than currently used mon omer methylmethacrylate. Preincubation of polymers in serum containing medi um was found to increase the biocompatibility of the polymers. High levels of apoptosis occurred on polymer used directly after polymerization, Apopto sis levels were decreased after polymer was incubated at 60 degreesC overni ght or for 3 days. Apoptosis therefore may occur in cells at the implant si te in vivo. (C) 2001 John Wiley & Sons, Inc.