Macrophage phagocytosis of polyethylene particulate in vitro

grantor: University of TorontoPolyethylene particles are the major constituents of the material debris formed as a result of orthopaedic implant wear. The purpose of this study was to develop an 'in vitro' model which would allow the introduction of polyethylene particulate into macrophages. UBMWPE (18-20 [mu]m) and HDPE (4-10 [mu]m) were characterized by XPS and FT-IR and suspended in soluble collagen type I which was subsequently solidified on glass coverslips. Mouse cell line macrophages (IC-21) were established on the collagen-particle substrata and maintained for up to 96 hours. The response of the cells to the particles was examined by light microscopy, TEM, and SEM. Histological analysis of the samples revealed that the macrophages surrounded larger particles (18-20 [mu]m) and the cells appeared to be attached to the surface of the particles, while the smaller particles (4-10 [mu]m) had been phagocytosed within two hours. Inflammatory cytolcines, lysosomal enzymes, and prostaglandin E2 were released into the medium, and IL-1Ã, IL-1ß, PGE2, ß-galactosidase and hexosaminidase levels were significantly increased over control values. These results validate the model as means of studying the specific ' in vitro 'interactions of polyethylene with cells.M.A.Sc