Effects of basic fibroblast growth factor on the remodeling of alveolar bone

为了维持健康的牙周组织，需要足够的支持性牙槽骨体积。牙周组织中成骨细胞和破骨细胞之间协调的细胞功能调控着持续的骨重建。另一方面，我们已经证明，局部应用成纤维细胞生长因子-2（FGF-2）诱导显着的牙周组织regeneration.In这项研究中，我们检查FGF-2对破骨细胞在牙周组织中的作用。免疫组化分析显示，FGF-2分布在牙周膜细胞，牙龈成纤维细胞和破骨细胞在比格犬牙周组织与自然发生的牙周炎。在体外研究中，我们通过用可溶性RANKL（NF-κB配体的受体激活剂）刺激细胞3天，成功地从小鼠骨髓单核细胞（RAW 264）中诱导多核破骨细胞。此外，我们证明FGF-2对可溶性RANKL刺激下RAW 264细胞破骨细胞的形成没有直接影响。然而，FGF-2刺激的小鼠克隆性牙周韧带细胞（MPDL-22）和牙龈成纤维细胞（MG/B6）的条件培养基显示出对破骨细胞形成的抑制作用，但不影响破骨细胞的成熟。用抗OPG（骨保护素）mAb预处理条件培养基可恢复这种抑制作用。此外，FGF-2上调MPDL-22和MG/B6中OPG和RANKL mRNA的表达。这些结果表明，FGF-2诱导的牙周组织细胞产生的OPG可以抑制牙周组织中破骨细胞的形成，并可能反过来支持牙槽骨的形成。

In order to maintain the healthy periodontal tissue, adequate supportive alveolar bone volume is required. Continuous bone remodeling is regulated by orchestrated cellular functions between osteoblasts and osteoclasts in periodontal tissue. On the other hand, we have already demonstrated that topical application of fibroblast growth factor-2 (FGF-2) induced significant periodontal tissue regeneration.In this study, we examined the effects of FGF-2 on osteoclastogenesis in periodontal tissues. Immunohistochemical analysis revealed that FGF-2 is distributed on the periodontal ligament cells, gingival fibroblasts and osteoclasts in the periodontal tissue of beagle dogs with naturally occurring periodontitis. In in vitro studies, we successfully induced multinucleated osteoclasts from murine myelomonocytic cells (RAW264) by stimulating the cells with soluble RANKL (receptor activator of NF-κB ligand) for 3 days. Furthermore, we demonstrated that FGF-2 had no direct effects on the osteoclast formation from RAW264 cells under the stimulation with soluble RANKL. Interestingly, however, the conditioned medium of FGF-2-stimulated murine clonal periodontal ligament cells (MPDL-22) and gingival fibroblasts (MG/B6) showed the inhibitory effects on the osteoclast formation, but did not influence the maturation of the osteoclasts. This inhibitory effect was restored by the pretreatment of conditioned medium with anti-OPG (osteoprotegerin) mAb. In addition, FGF-2 upregulated the OPG and RANKL mRNA expressions in MPDL-22 and MG/B6. These results suggest that FGF-2-induced OPG produced from periodontal tissue cells can inhibit osteoclast formation in the periodontal tissue and may in turn support the alveolar bone formation.