[Influence of titanium particles loading on releases of cytokines of osteoblasts]

Aseptic loosening is mainly mediated by bone resorption cytokines in the surrounding area of orthopaedic implants. Our previous investigation demonstrtated that different-sized titanium particles loading can inbibit the osteoblastic differentiation and mineraliztion. In order to investigate the hypothesis that particulate wear debris derived from prosthetic biomaterials affects the release of bone resorption related cytokines, we studied the influence of different-sized titanium particles loading on the osteoblastic cytokines by assaying the secretion of IL-6, IL-10 with use of ABC-quantitative sandwich enzyme-linked immunosorbent assay, and on the expression of osteoclast differentiation factors (ODF) by RT-PCR. The results showed that the 0.9 microm titanium particles promoted osteoblasts producing bone resorption cytokines (IL-6, ODF), and simultaneously secreted bone absorption restraining factor (IL-10) quickly and transitorily. In comparison, the 2.7 microm and 6.9 microm titanium particles,especially the latter primarily promoted osteoblasts secreting bone absorption promoting factors powerfully and slowly. The results suggested that there was a biphasic response appearing in titanium particles loaded-osteoblastic cultures, the level of which varied according to the different size and the loading time of titanium particles. This in vitro experimental result showed that attentaion to the inhibition of bone resorption cytokines stimulated by wear debris and to the screen potential favourable biomaterials for implants must be taken.