Acceleration of bone healing process by local application of the resorbable collagen pellet containing basicfibroblast growth factor (FGF-2)

我们进行了一项动物研究，以确定是否可以通过使用一种新的药物递送系统控制应用碱性成纤维细胞生长因子（FGF-2）来加速膜保护骨缺损的再生。首先，我们在体外研究了FGF-2对原代培养犬生长板软骨细胞矿化过程的影响。从1周龄犬肋生长板中分离软骨细胞。软骨细胞在含有10%胎牛血清和50马克杯/毫升抗坏血酸的a-MEM培养皿中以极高的密度（5 × 10^4个细胞/孔）保存。矿化发生在第20 ~ 24天；然而，加入成纤维细胞生长因子(FGF)-2 （1.0 ng/ml）抑制矿化。其次，我们使用比格犬进行了体内研究。对9只比格犬进行了牙槽骨缺损的手术治疗，并使用特制的胶原颗粒给予FGF-2。将含有0.15杯FGF-2 （FGF）或0杯FGF-2（安慰剂）的小颗粒放置在缺损处或不使用小颗粒（对照组），术后8周对骨再生进行放射学、组织学和组织形态学评估。x线片显示，与安慰剂或对照部位相比，FGF部位的透射线区域大得惊人。组织学上，成熟骨填充了FGF部位膜保护缺损的大部分内部空间。在对照组和安慰剂组也可以观察到新骨的形成，然而，它填充了不足一半的缺损区域。组织形态学上，FGF部位再生骨面积显著高于其他部位（p<0.01）。这些结果表明，有控制地应用FGF-2可促进膜保护骨缺损的骨再生。

We performed an animal study to ascertain whether the regeneration of membrane-protected bone defects can be accelerated by the controlled application of basic fibroblast growth factor (FGF-2) using a new drug delivery system. First, we investigated in vitro effects of FGF-2 on the mineralization process in primary cultures of dog growth plate chondrocytes. Chondrocytes were isolated from the growth plates of ribs of 1-week-old dogs. The chondrocytes were maintained at extremely high density (5 x 10^4 cells/well) on collagen-coated 96-well dishes in a-MEM with 10% fetal bovine serum and 50 mug/ml ascorbic acid. Mineralization was initiated between days 20 and 24 ; however, the addition of fibroblast growth factor (FGF)-2 (1.0 ng/ml) suppressed mineralization. Second, we performed in vivo study using beagle dogs. Alveolar bone defects were made surgically in 9 beagle dogs, and FGF-2 was administered using specially made collagen pellets. A pellet containing either 0.15 mug FGF-2 (FGF) or 0 mug FGF-2 (placebo) was placed in the defect or no minipellet was used (control), and bone regeneration was evaluated radiologically, histologically, and histomorphometrically 8 weeks after the operation. X-ray radiographs showed a surprisingly large radiopaque region in FGF sites compared with placebo or control sites. Histologically, mature bone filled the majority of the inner space of the membrane-protected defect in FGF sites. New bone formation was also seen in the control and the placebo sites, however, it filled less than half the area of the defect. Histomorphometrically, the area of regenerated bone in FGF sites was significantly higher than in the other sites (p<0.01). These results demonstrate that the controlled application of FGF-2 accelerates bone regeneration in membrane-protected bone defects.