Jiang D, Dziak R, Lynch S E, Stephan E B
Department of Oral Biology, SUNY at Buffalo School of Dental Medicine, NY 14214, USA.
J Periodontol. 1999 Aug;70(8):834-9. doi: 10.1902/jop.1999.70.8.834.
Osteoconductive anorganic bovine bone mineral matrix material has been used clinically in bone regeneration procedures. Platelet-derived growth factor-BB (PDGF-BB) and insulin-like growth factor (IGF-I) are important anabolic growth factors for bone. It was the aim of these studies to 1) examine the interaction of this bone graft material with PDGF-BB and IGF-I and 2) determine if the combination of growth factors with the matrix could stimulate osteoblastic cell proliferation.
Adsorption of PDGF-BB and IGF-I was done using 125I radio-labeled growth factors. The PDGF-BB or IGF-I was incubated with the anorganic bovine bone matrix, and the amount of adsorbed growth factor was measured. In the desorption studies, radiolabeled growth factors were adsorbed to the matrix material. The samples were incubated in buffer for various time periods, and the amount remaining on the matrix was measured to calculate the percentage of released growth factor. The biological activity was tested in an in vitro assay with primary culture neonatal rat osteoblastic cells. Porous bone matrix with known amounts of adsorbed PDGF-BB or IGF-I was produced. The osteoblastic cells were cultured on the bone mineral matrix, with and without adsorbed growth factor, and proliferation was assessed by 3H-thymidine incorporation.
Both PDGF-BB and IGF-I adsorbed to bone mineral matrix in a concentration-dependent fashion. The affinity of IGF-I for the material was 10-fold greater than PDGF-BB. In the experiments that measured the release of the initially adsorbed growth factors, approximately 50% of the PDGF-BB and 10% of the IGF-I were released after 10 days. PDGF-BB adsorbed to the matrix material significantly (P <0.05, ANOVA) enhanced the proliferation of cultured osteoblastic cells compared to the mineralized matrix alone. However, IGF-I adsorbed to the matrix material did not significantly enhance cell proliferation.
These results suggest that PDGF-BB can be adsorbed to the anorganic bovine bone mineral matrix and that this growth factor subsequently enhances the osteogenic properties of this bone graft material. IGF-I also adsorbed to the graft material; however, it was not readily released and it did not produce significant effects in the biologic assay. It appears that it may be clinically feasible to adsorb PDGF to anorganic bovine bone and that this combination of bone growth factor and mineral matrix has the potential for clinical applications.
骨传导性无定形牛骨矿物质基质材料已在骨再生手术中临床应用。血小板衍生生长因子-BB（PDGF-BB）和胰岛素样生长因子（IGF-I）是骨重要的合成代谢生长因子。这些研究的目的是：1）研究这种骨移植材料与PDGF-BB和IGF-I的相互作用；2）确定生长因子与基质的组合是否能刺激成骨细胞增殖。
使用125I放射性标记的生长因子进行PDGF-BB和IGF-I的吸附。将PDGF-BB或IGF-I与无定形牛骨基质孵育，测量吸附的生长因子量。在解吸附研究中，将放射性标记的生长因子吸附到基质材料上。将样品在缓冲液中孵育不同时间段，测量留在基质上的量以计算释放的生长因子百分比。用原代培养新生大鼠成骨细胞的体外试验测试生物活性。制备含有已知量吸附PDGF-BB或IGF-I的多孔骨基质。将成骨细胞培养在骨矿物质基质上，有或没有吸附的生长因子，通过3H-胸苷掺入评估增殖。
PDGF-BB和IGF-I均以浓度依赖性方式吸附到骨矿物质基质上。IGF-I对该材料的亲和力比PDGF-BB高10倍。在测量最初吸附的生长因子释放的实验中，10天后约50%的PDGF-BB和10%的IGF-I被释放。与单独的矿化基质相比，吸附到基质材料上的PDGF-BB显著（P<0.05，方差分析）增强了培养的成骨细胞的增殖。然而，吸附到基质材料上的IGF-I没有显著增强细胞增殖。
这些结果表明，PDGF-BB可以吸附到无定形牛骨矿物质基质上，并且这种生长因子随后增强了这种骨移植材料的成骨特性。IGF-I也吸附到移植材料上；然而，它不容易释放，并且在生物学试验中没有产生显著影响。看来将PDGF吸附到无定形牛骨上在临床上可能是可行的，并且这种骨生长因子和矿物质基质的组合具有临床应用潜力。
