Effect of polyethylene particles on human osteoblastic cell growth

In this study, we have analyzed the direct effect of ultrahigh molecular weight polyethylene (polyethylene) on the osteoblastic cell growth in primary cultures. The cells were cultured from human bone samples obtained during reconstructive joint surgery. When cell cultures reached confluence (4-6 weeks) they were separated into three subcultures. One subculture was without particle addition (plain culture). In the other two subcultures, polyethylene or alumina was added. Two different sizes of particles were used, < 80 and < 160 μm. The subcultures were incubated until confluence. Proliferation of each subculture was measured by cell counts after 3, 6, 9 and 13 days, and the area under the curve (AUC) was calculated. Polyethylene particles of < 160 μm induced a decrease in growth, whereas alumina of the same size did not. Polyethylene and alumina particles of < 80 μm induced an inhibition in the osteoblastic cell growth; < 80 μm polyethylene induced a higher inhibition than alumina of the same particle size. In conclusion, we have observed a direct effect of polyethylene on osteoblastic cell growth. This study shows that polyethylene may decrease the growth rate of human osteoblastic cells in primary cultures. Smaller particles produce a more marked reduction.