Lewandrowski K U, Gresser J D, Bondre S, Silva A E, Wise D L, Trantolo D J
Orthopaedic Research Laboratories, Massachusetts General Hospital, Boston 02114, USA.
J Biomater Sci Polym Ed. 2000;11(8):879-89. doi: 10.1163/156856200744075.
Bioresorbable bone graft substitutes could eliminate disadvantages associated with the use of autografts, allografts and other synthetic materials. We investigated a bioresorbable bone graft substitute made from the unsaturated polyester poly(propylene fumarate) which is crosslinked in the presence of soluble and insoluble calcium filler salts. This compact bone graft substitute material develops porosity in vivo by leaching of the soluble filler salts. In attempt to develop materials whose in vivo porosity can be designed such that implant degradation would occur at a rate that remains supportive of the overall structural integrity of the repairing defect site, we studied the early tissue response upon implantation in a bony defect. Three grout formulations of varying solubilities using slightly soluble hydroxyapatite (HA) and soluble calcium acetate (CA) were evaluated in 3 mm holes made in the anteromedial tibial metaphysis of 200 g Sprague Dawley rats (n = 16 per formulation for a total of 48 animals). Grout formulations cured in situ. Animals from each formulation were sacrificed in groups of 8 at 4 days and 3 weeks postoperatively. Histologic analysis of the healing process revealed improved in vivo osteointegration of bone graft substitutes when a higher loading of calcium acetate was employed. All formulations maintained implant integrity and did not provoke sustained inflammatory responses. This study suggested that the presence of a soluble salt permits in vivo development of porosity of a poly(propylene fumarate) based bone graft substitute material.
生物可吸收骨移植替代物可以消除与使用自体骨、异体骨和其他合成材料相关的缺点。我们研究了一种由不饱和聚酯聚（富马酸丙二醇酯）制成的生物可吸收骨移植替代物，该聚酯在可溶性和不溶性钙填充盐存在下交联。这种致密的骨移植替代材料通过可溶性填充盐的浸出在体内形成孔隙。为了开发体内孔隙率可以设计的材料，使植入物降解的速度能够支持修复缺损部位的整体结构完整性，我们研究了植入骨缺损后早期的组织反应。在200克斯普拉格-道利大鼠的胫骨干骺端前内侧制作的3毫米孔中，评估了三种使用微溶性羟基磷灰石（HA）和可溶性醋酸钙（CA）的不同溶解度的灌浆配方（每种配方16只动物，共48只动物）。灌浆配方在原位固化。每组配方的动物在术后4天和3周时以每组8只的方式处死。愈合过程的组织学分析表明，当使用较高含量的醋酸钙时，骨移植替代物的体内骨整合得到改善。所有配方都保持了植入物的完整性，并且没有引发持续的炎症反应。这项研究表明，可溶性盐的存在允许基于聚（富马酸丙二醇酯）的骨移植替代材料在体内形成孔隙。
