Department of Biomaterials, Radboud University Nijmegen Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
Biomed Mater. 2013 Jun;8(3):035012. doi: 10.1088/1748-6041/8/3/035012. Epub 2013 Apr 26.
Calcium phosphate cements (CPCs) including poly(D,L-lactic-co-glycolic) acid (PLGA) microparticles are promising candidates for bone regenerative applications. Previous studies with CPC/PLGA demonstrated that the material is non-toxic, biocompatible and osteoconductive. However, the outcome of these studies was based on healthy individuals and consequently does not provide information on bone substitute material performance in a compromised situation, such as osteoporosis. Therefore, this study comparatively evaluated the performance of injectable CPC/PLGA in healthy (SHAM) and osteoporotic rats (OVX) using a rat femoral condyle defect with implantation periods of 4 and 12 weeks. It was hypothesized that in OVX rats the degradation of CPC/PLGA would increase due to a higher osteoclastic activity present in osteoporotic animals and that the obtained space would be rapidly filled with newly formed bone. The results revealed an accelerated degradation of the used CPC/PLGA in osteoporotic animals, but bone formation was less compared to that in healthy animals at 4 and 12 weeks after implantation. In addition, after 4 weeks, the amount of newly formed bone under osteoporotic conditions was less in the femoral condyle defect compared to that present in a non-defect, osteoporotic control femoral condyle, but equal after 12 weeks. On the other hand, in healthy animals, the amount of newly formed bone in the femoral condyle defect was equal to that present in a non-defect control femoral condyle at 4 weeks, while higher after 12 weeks. This indicates that bone regeneration at a defect site under osteoporotic conditions is slower, but can reach native amounts after longer time periods. Consequently, bone regenerative treatments under osteoporotic conditions seem to require additional empowerment of bone substitute materials.
磷酸钙骨水泥（CPCs）包括聚（D，L-丙交酯-共-乙交酯）（PLGA）微球，是骨再生应用的有前途的候选材料。以前使用 CPC/PLGA 的研究表明，该材料是无毒、生物相容和骨传导的。然而，这些研究的结果是基于健康个体得出的，因此不能提供材料在受损情况下（如骨质疏松症）的骨替代物性能的信息。因此，本研究通过大鼠股骨髁缺损比较评估了可注射 CPC/PLGA 在健康（SHAM）和骨质疏松（OVX）大鼠中的性能，植入期为 4 周和 12 周。假设在骨质疏松动物中，由于破骨细胞活性较高，CPC/PLGA 的降解会增加，并且获得的空间会迅速被新形成的骨填充。结果表明，在骨质疏松动物中，所用 CPC/PLGA 的降解速度加快，但与植入后 4 周和 12 周的健康动物相比，骨形成较少。此外，在植入后 4 周，与非缺陷性骨质疏松对照组股骨髁相比，骨质疏松条件下股骨髁缺损处新形成的骨量较少，但在植入后 12 周时相等。另一方面，在健康动物中，在植入后 4 周时，股骨髁缺损处新形成的骨量与非缺陷性对照组股骨髁相等，而在植入后 12 周时更高。这表明，在骨质疏松条件下，缺损部位的骨再生较慢，但在较长时间后可以达到正常水平。因此，在骨质疏松条件下进行的骨再生治疗似乎需要增强骨替代材料的作用。
