ABSTRACT
PURPOSE: We hypothesize that the presence of barium sulfate debris plays an influential role to deteriorate the balance of bone remodelling around prosthesis via cytotoxic mechanism to osteoblast. MATERIALS AND METHODS: Osteoblasts were obtained from the neonatal rat calvarium, and SiO2, TiO2 , PMMA and BaSO4 particles were prepared for the evaluation of particle induced cytotoxicity to osteoblast. Osteoblasts were grown in DMEM and then were seeded into 6 well culture plates. 1.0wt% solution of each particle was added to culture medium to generate a final concentration of 0.1wt%, and 0.005wt% of various particles in each well, respectively. The measurement of intracellular calcium was conducted using various agonists of calcium. The cell viability assay for osteoblast was performed with MTT reduction assay and the mineralization of the matrix was checked by Von Kossa staining. ELISA kit was used to quantify the level of osteocalcin in osteoblast. RESULTS: BaSO4 significantly lowered the cell viability. All particles except TiO2 increased [Ca(2+)]i transiently, and the rank of differential cytosolic [Ca(2+)]i was in order as follows; SiO2, BaSO4, and PMMA. The mineralization was significantly prohibited in SiO2 and BaSO4(0.1wt%), however the PMMA showed no definite inhibitory effect on bone mineralization. PMMA(0.1wt%) and BaSO4(0.1wt%) showed significantly inhibitory effect on osteocalcin production. CONCOUSION: In higher concentration, BaSO4 has a cytotoxic effect on osteoblast and inhibitory effect of osteocalcin production as well as mineralization of osteoblast. Also, this study has shown that the concentration of intracellular calcium is strongly influenced by exposure to BaSO4 particles in vitro. The effect of BaSO4 on osteoblast observed in this study could have implications for the role of BaSO4 particles on osteoblast function at aseptic loosening of cemented total joint arthroplasty.