Xing Zhiqing, Schwab Luciana P, Alley Carie F, Hasty Karen A, Smith Richard A
Department of Orthopaedic Surgery, University of Tennessee-Campbell Clinic, Memphis, Tennessee 38163, USA.
J Biomed Mater Res B Appl Biomater. 2008 Apr;85(1):37-41. doi: 10.1002/jbm.b.30913.
Titanium particles derived from the wear of the orthopaedic implant surfaces can activate macrophages to secrete cytokines and stimulate osteoclastic bone resorption, causing osteolysis around orthopaedic implants. However, what happens to the titanium particles after being phagocytosed by macrophages is not known. We prepared titanium particles (as received, clean, and LPS-coated), and exposed them to macrophages in culture. Free particles were washed away after 24 h and the intracellular particles were kept in culture for additional 48 h until being harvested by lysing the cells. Particles that had been cell treated or noncell treated were examined by scanning electronic microscopy to analyze the shape, size, and concentration of the particles. The cell treated and noncell treated particles were exposed to macrophages in culture with a particle to cell ratio of 300:1. After 18 h, the levels of TNF-alpha in culture medium and the viability of the cells were examined. Clean particles did not stimulate TNF-alpha secretion by macrophages, while LPS-coated particles dramatically increased that response. Phagocytosis by macrophages did not change the shape and size of the particles, but depleted the ability of the particles to stimulate TNF-alpha secretion by macrophages. This indicates that macrophages are capable of rendering titanium particles inactive without degrading the particles, possibly by altering the surface chemistry of the particles.
骨科植入物表面磨损产生的钛颗粒可激活巨噬细胞分泌细胞因子并刺激破骨细胞的骨吸收，导致骨科植入物周围发生骨溶解。然而，钛颗粒被巨噬细胞吞噬后会发生什么尚不清楚。我们制备了钛颗粒（原样、清洁和脂多糖包被），并将它们暴露于培养的巨噬细胞中。24小时后洗去游离颗粒，将细胞内颗粒继续培养48小时，直到通过裂解细胞进行收获。对经过细胞处理或未经过细胞处理的颗粒进行扫描电子显微镜检查，以分析颗粒的形状、大小和浓度。将经过细胞处理和未经过细胞处理的颗粒以300:1的颗粒与细胞比例暴露于培养的巨噬细胞中。18小时后，检测培养基中肿瘤坏死因子-α（TNF-α）的水平和细胞活力。清洁颗粒不会刺激巨噬细胞分泌TNF-α，而脂多糖包被的颗粒则显著增强了这种反应。巨噬细胞的吞噬作用不会改变颗粒的形状和大小，但会削弱颗粒刺激巨噬细胞分泌TNF-α的能力。这表明巨噬细胞能够在不降解颗粒的情况下使钛颗粒失活，可能是通过改变颗粒的表面化学性质来实现的。
