Elucidation of the mechanism of alveolar bone regeneration by controlled release of recombinant human FGF-2

我们分析了明胶水凝胶控释成纤维细胞生长因子2诱导小鼠骨再生的生物学机制。2005年在日本科学研究资助计划的资助下建立了牙槽骨再生模型。明胶水凝胶植入后7-14天，FGF-2释放组（实验组）骨膜中PCNA指数显著高于对照组。实验组骨膜增生，碱性磷酸酶活性阳性，骨痂形成。用地高辛标记的碱性磷酸酶、骨钙素、骨桥蛋白、FGFR-1、FGFR-2和Runx 2的cRNA探针进行原位杂交，以检测成骨细胞的成熟以及FGFR-1、FGFR-2和Runx 2在FGF 2诱导的增生骨膜中的表达分布。在愈伤组织和原始组织的表面观察到表达骨钙蛋白、骨桥蛋白和碱性磷酸酶的成熟成骨细胞 关于我们 骨头另外，仅表达碱性磷酸酶的未成熟成骨细胞广泛分布于骨膜中。而Fgfr-1、Fgfr-2在成熟成骨细胞中的表达较未成熟成骨细胞强，骨膜外部分梭形细胞也表达Fgfr-1、Fgfr-2。Runx 2与Fgfr-1和Fgfr-2信号共定位于骨膜中。采用真实的时间RT-PCR检测激光显微切割后骨膜中这些基因的表达水平。实验组Runx 2、骨钙素、骨桥蛋白和碱性磷酸酶的表达明显高于对照组。Fgfr-1和Fgfr-2在实验组的表达水平也高于对照组。可以得出结论，在骨膜中控制释放FGF 2通过骨痂形成促进附加骨再生，这是由于FGF 2的合成代谢作用不仅促进成骨细胞增殖，而且增强骨基质产生。此外，在这项研究中，我们发现，FGF 2上调Runx 2的表达与骨钙素，骨桥蛋白和碱性磷酸酶的表达与以前的体外实验报告的结果相反。少

We analyzed biological mechanism of the bone regeneration induced by controlled release of FGF2 using gelatin hydrogel in mouse. The alveolar bone regeneration model have established in 2005 supported by Grant-in-Aids for Scientific Research from JSPS. Through 7-14 days after implantation of the gelatin hydrogel, PCNA index in the periosteum of the FGF-2 released group (experimental group) was significantly higher than the control group. And hyperplastic periosteum with positive responses of alkaline phosphatase activity was observed with callus formation in the experimental group. In situ hybridization was performed using DIG-labeled cRNA probes for alkaline phosphatase, osteocalcin, osteopontin, Fgfr-1, Fgfr-2 and Runx2 to detect osteoblast maturation and distribution of the Fgfr-1, Fgfr-2 and Runx2 expression in the FGF2 induced hyperplastic periosteum. Mature osteoblast expressing osteocalcin, osteopontin and alkaline phosphatase was observed on a surface of the callus and original … More bone. Beside, immature osteoblast expressing only alkaline phosphatase showed widespread distribution in the periosteum. Whereas, Fgfr-1 and Fgfr-2 signal were greater in mature osteoblast than immature osteoblast, and some spindle shaped Cells out of the periosteum also expressed Fgfr-1, Fgfr-2. Runx2 was colocalyzed in periosteum with the signals of Fgfr-1 and Fgfr-2. Furthermore, expression level of these genes in laser micro-dissected periosteum were analyzed by real time RT-PCR. In experimental group, Runx2, osteocalcin, osteopontin and alkaline phosphatase expression were significantly higher than control group. Fgfr-1 and Fgfr-2 expression level were also higher in the experimental group than those of the control group. It can be concluded that controlled release of FGF2 in periosteum promotes additive bone regeneration through callus formation as a result of anabolic effects of FGF2 not merely promoting osteogenic cell proliferation but also enhancement of bone matrix production. Moreover, in this study we showed that FGF2 up-regulates Runx2 expression revel in the tissue as with osteocalcin, osteopontin and alkaline phosphatase expression contrary to results of previous in vitro experiment reports. Less