ACUTE TOXICITY OF METAL-IONS IN CULTURES OF OSTEOGENIC CELLS DERIVED FROM BONE-MARROW STROMAL CELLS

The effects of metal ions released from orthopedic implants on nearby bone cells remain largely unknown, The purpose of this study was to ex amine the acute toxicity of metal ions on osteogenic cells derived fro m bone marrow, Bone marrow stromal cells were cultured with metal ions found in commonly used orthopedic implants, that is, Ti-6Al-4V, Co-Cr -Mo, and 316L stainless steel, Solutions of individual ions and combin ations representing the alloy composition were prepared from atomic ab sorption standards and added to the cultures to give concentrations ra nging from 50 ppb to 50 ppm. After a 48-h period of exposure to ions, the bone marrow cultures were examined for effects of cytotoxicity by measuring total cell number, total cell protein, and mitochondrial act ivity, Cr6+ was grossly cytotoxic; Co2+, Mo6+, Fe3+, and Ni2+ were mod erately cytotoxic; and Ti4+, Al3+, V5+, and Mn2+ were minimally toxic, as determined by the assays used, Ion solutions representing Co-Cr-Mo and 316L stainless steel were moderately toxic; solutions representin g Ti-6Al-4V were toxic at only the highest concentrations used, The ob served cytotoxicity was time-dependent, with irreversible toxic effect s being initiated following as short as a 3- to 6-hour exposure, These results show that metal ions associated with Co-Cr-Mo and 316L stainl ess steel are toxic to osteogenic cells at concentrations approximatin g those measured in the fibrous membrane encapsulating orthopedic impl ants. (C) 1995 John Wiley and Sons, Inc.