The Influence Of Ti6Al4V, PMMA, UHMWPE And Co-Cr Particles On Human Peripheral Blood Monocytes In Vitro

Objective:Aseptic loosening of total joint replacements is believed to be initiated by a macrophage response to prosthetic wear debris. To better characterize the initial response to clinically relevant wear debris, we challenged human monocytes with Ti6A14V, PMMA, UHMWPE and Co-Cr particles. In addition, we attempt to further investigate the wear particles induced bone dissolution reaction mechanism of possible role in aseptic loosening.Methods:Human monocytes were isolated from volunteer whole blood. Cell count and viability were assessed with trypan blue dye exclusion. Purified monocytic cells were cultured with all kinds of wear particles in 6-well tissue culture plates. Being dependent on the type of the particles, we divided into four groups (A: monocytes+Ti6A14V particles group; B:monocytes+PMMA particles group; C: monocytes+UHMWPE particles group; D:monocytes+Co-Cr particles group). Each group added particle number according to the particle/cell ratio of 0,0.1,1,10,100, 1000. After a 72h culture, ELISA technique was utilized to quantify the secretion of different cytokines includes TNF-?, IL-1 and IL-6. We observed the influence of particle concentration on monocytes in groups and particle properties between groups.Results:Cell viability was exceeding 95% for all trials, in addition to the group D particle/cell ratio of 1000. The cell survival rate was reduced to 87%. ELISA demonstrated that compared with the naive monocytes (particle/cell ratio of 0), the expression of TNF-?,IL-1 and IL-6 increased significantly 72h after human monocytes challenged by Ti6A14V, PMMA, UHMWPE and Co-Cr particles. It's having a statistically significant difference (P<0.05). Ti6A14V, PMMA and UHMWPE particles can stimulate human monocytes to over-express TNF-?, IL-1 and IL-6, which are positively correlated with the concentration of particles. However, when the Co-Cr particle/cells ratio reaches 1000, expression level of TNF-? and IL-1 and IL-6 was decreased. Either particle/cell ratio was 10 or 100 or 1000, Ti6A14V particles had caused TNF-?, IL-1 and IL-6 highest expression level. Ti6A14V particles had the most stimulated. Co-Cr particles and PMMA particles had mildly stimulated and UHMWPE particles were significantly less stimulated than other debris.Conclusion:Four types of wear particles with different function of biological activity for monocytes having dose dependent in the initial stage of the osteolysis reaction. Ti6A14V particles strong biological activity and Co-Cr particles exist certain cytotoxicity tip may be the key factors affecting initial stage of the osteolysis, the increasingly accumulation and hard to degradation of PMMA and UHMWPE particles may be plays an important role in the terminal phase of the osteolysis and pseudo granuloma formation.