Faculty of Dentistry, National University of Singapore, Singapore, Singapore.
Connect Tissue Res. 2013;54(2):101-7. doi: 10.3109/03008207.2012.751985. Epub 2013 Jan 18.
The success of periodontal regeneration depends on the coordination of early cell proliferation and late cell differentiation. The aim of this study was to investigate whether the proliferation or differentiation stage predominantly promotes the initiation of periodontal regeneration. Critical-sized periodontal defects were surgically created on rat maxillae and filled with poly-(D,L-lactide-co-glycolide)-poly-d,l-lactide hybrid microspheres encapsulating platelet-derived growth factor (PDGF, a promoter of mitogenesis), simvastatin (a promoter of osteogenic differentiation), or bovine serum albumin (a control). The encapsulation efficiency and in vitro release profiles of the microspheres were determined by high-performance liquid chromatography and enzyme-linked immunosorbent assay. The maxillae were harvested after 10 or 14 days and assessed by micro-computed tomography, histology, and immunohistochemistry for regeneration efficacy and cell viability. The rapid release of PDGF was observed within the first week, whereas a slow release profile was noted for simvastatin. The PDGF-treated specimens demonstrated a significantly higher bone volume fraction compared with bovine serum albumin- (p < 0.05) or simvastatin-treated (p < 0.05) specimens at day 14. Histologically, active bone formation originating from the defect borders was noted in both the PDGF- and the simvastatin-treated specimens, and functionally aligned periodontal ligament fiber insertion was only observed in the PDGF-treated specimens. The significant promotion of mitogenesis by PDGF treatment was also noted at day 14 (p < 0.05). In conclusion, increased mitogenesis or osteogenic differentiation may stimulate osteogenesis, and the upregulation of mitogenesis by PDGF appears to play a role in the initiation of periodontal regeneration.
牙周组织再生的成功取决于早期细胞增殖和晚期细胞分化的协调。本研究旨在探讨增殖期或分化期更能促进牙周组织再生的起始。在大鼠上颌骨上用手术创建临界尺寸的牙周缺损，并填充聚（D，L-丙交酯-co-乙交酯）-聚-d，l-丙交酯杂化微球，包封血小板衍生生长因子（PDGF，促有丝分裂原），辛伐他汀（促成骨分化）或牛血清白蛋白（对照）。通过高效液相色谱法和酶联免疫吸附试验测定微球的包封效率和体外释放曲线。在第 10 天或第 14 天收获上颌骨，并通过微计算机断层扫描、组织学和免疫组织化学评估再生效果和细胞活力。在第 14 天，与牛血清白蛋白（p <0.05）或辛伐他汀（p <0.05）处理的标本相比，PDGF 处理的标本的骨体积分数显著更高。组织学上，在 PDGF 和辛伐他汀处理的标本中均观察到源自缺陷边界的活跃骨形成，仅在 PDGF 处理的标本中观察到功能排列的牙周韧带纤维插入。在第 14 天还观察到 PDGF 处理促进有丝分裂（p <0.05）。总之，PDGF 治疗可促进有丝分裂或成骨分化，PDGF 上调有丝分裂似乎在牙周组织再生的起始中发挥作用。
