[In vitro toxicity tests of bioceramics and bone transplants in fibroblast culture]

Prior to the clinical use of synthetic bone substitutes and allogenic bone transplants, potential toxicity resulting from various different manufacturing, storage, and sterilisation techniques should be excluded. In order to develop a reliable and reproducible in vitro model for the investigation of possible tissue reactions after implantation of biomaterials, we modified an established animal fibroblast culture technique used to test chemical agents for acute unspecific cytotoxicity. Subcultivation of human fibroblasts produces stable monolayer cultures with the aid of which, standardised, accurate and reproducible evaluation of toxic effects, as well as the direct visualisation of fibroblast ingrowth into porous implant material, is possible. Gamma-irradiated synthetic implants and bovine hydroxyapatite failed to show any substantial cytotoxicity. In contrast, ethylene oxide sterilised implant material, as well as fresh untreated trabecular bone showed a significant toxic effect in comparison with cryopreserved and autoclaved trabecular bone.