van Minnen B, van Leeuwen M B M, Kors G, Zuidema J, van Kooten T G, Bos R R M
Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, University of Groningen, P.O. Box 30.001, 9700 RB Groningen, The Netherlands.
J Biomed Mater Res A. 2008 Jun 15;85(4):972-82. doi: 10.1002/jbm.a.31574.
Degradable polyurethanes (PUs), based on aliphatic diisocyanates, can be very useful in tissue regeneration applications. Their long-term in vivo degradation has not been extensively investigated. In this study a biodegradable PU with copolyester soft segments of DL-lactide/epsilon-caprolactone and hard segments synthesized from 1,4-butanediisocyanate was evaluated with regard to tissue response during degradation and, ultimately, the resorption of the material. Highly porous PU foam discs were subcutaneously implanted in rats and rabbits for intervals up to 3 years. A copolymer foam of DL-lactide and epsilon-caprolactone served as a control. The foams, the surrounding tissues and the draining lymph nodes were evaluated with light and electron microscopy. In the first stages of degradation the number of macrophages and giant cells increased. As the resorption stage set in their numbers gradually decreased. Electron microscopy showed macrophages containing pieces of PU. The size of the intracellular PU particles diminished and cells containing these remnants gradually disappeared after periods from 1 to 3 years. After 3 years an occasional, isolated macrophage with biomaterial remnants could be traced in both PU and copolymer explants. Single macrophages with biomaterial remnants were observed in the lymph nodes between 39 weeks and 1.5 years following implantation. It is concluded that the PU foam is biocompatible during degradation. After 3 years PU samples had been resorbed almost completely. These results indicate that the PU foam can be safely used as a biodegradable implant.
基于脂肪族二异氰酸酯的可降解聚氨酯（PU）在组织再生应用中可能非常有用。其在体内的长期降解尚未得到广泛研究。在本研究中，对一种由DL-丙交酯/ε-己内酯的共聚酯软段和由1,4-丁二异氰酸酯合成的硬段组成的可生物降解PU进行了评估，以研究其在降解过程中的组织反应以及最终材料的吸收情况。将高度多孔的PU泡沫圆盘皮下植入大鼠和兔子体内长达3年。DL-丙交酯和ε-己内酯的共聚物泡沫用作对照。通过光学显微镜和电子显微镜对泡沫、周围组织和引流淋巴结进行评估。在降解的第一阶段，巨噬细胞和巨细胞的数量增加。随着吸收阶段的开始，它们的数量逐渐减少。电子显微镜显示巨噬细胞中含有PU碎片。细胞内PU颗粒的大小减小，含有这些残余物的细胞在1至3年后逐渐消失。3年后，在PU和共聚物外植体中偶尔能追踪到含有生物材料残余物的单个巨噬细胞。在植入后39周和1.5年之间，在淋巴结中观察到含有生物材料残余物的单个巨噬细胞。得出的结论是，PU泡沫在降解过程中具有生物相容性。3年后，PU样品几乎完全被吸收。这些结果表明，PU泡沫可以安全地用作可生物降解植入物。
