Okamoto Masanori, Dohi Yoshiko, Ohgushi Hajime, Shimaoka Hideki, Ikeuchi Masako, Matsushima Asako, Yonemasu Kunio, Hosoi Hiroshi
Department of Otolaryngology, Nara Medical University School of Medicine, Kashihara, Japan.
J Mater Sci Mater Med. 2006 Apr;17(4):327-36. doi: 10.1007/s10856-006-8232-z.
The in vitro and in vivo osteoblastic differentiation of rat bone marrow stromal cells (MSCs) was assessed on hydroxyapatite disks with 3 different porosities: 30%, 50%, and 70% (HA30, HA50, and HA70, respectively). MSCs obtained by 10-day culture of fresh bone marrow cells were subcultured for 2 weeks on 3 kinds of porous HA disks in the presence and absence of dexamethasone (Dex). After 2 weeks of subculture, alkaline phosphatase (ALP) activity and osteocalcin production of MSCs/HA composites with Dex were higher than those without, and increased with increasing porosity. The resultant bone tissue grafts "cultured-bone/HA constructs" were implanted subcutaneously into the backs of syngeneic rats, and harvested 1, 2, and 4 weeks after implantation. At 1 week, only cultured-bone/HA70 constructs exhibited expanded bone formation. At 2 and 4 weeks, active osteoblasts and progressive bone formation were observed morphologically in both cultured-bone/HA50 and HA70 constructs. At 4 weeks, bone tissue was observed even in cultured-bone/HA30 constructs. ALP activity and osteocalcin production also increased with increasing porosity and time after implantation. In this in vivo model, different scaffold porosity with similar crystal morphology of the apatite phase demonstrated marked differences in ability to support osteogenesis by implanted rat MSCs.
在具有3种不同孔隙率（分别为30%、50%和70%，即HA30、HA50和HA70）的羟基磷灰石圆盘上评估大鼠骨髓基质细胞（MSCs）的体外和体内成骨分化情况。通过对新鲜骨髓细胞进行10天培养获得的MSCs在存在和不存在地塞米松（Dex）的情况下，在3种多孔HA圆盘上进行传代培养2周。传代培养2周后，添加Dex的MSCs/HA复合材料的碱性磷酸酶（ALP）活性和骨钙素生成高于未添加Dex的情况，且随着孔隙率增加而升高。将所得骨组织移植物“培养骨/HA构建体”皮下植入同基因大鼠背部，并在植入后1、2和4周进行收获。在1周时，只有培养骨/HA70构建体表现出扩大的骨形成。在2周和4周时，在培养骨/HA50和HA70构建体中均在形态学上观察到活跃的成骨细胞和进行性骨形成。在4周时，甚至在培养骨/HA30构建体中也观察到了骨组织。ALP活性和骨钙素生成也随着孔隙率增加和植入后时间延长而增加。在这个体内模型中，磷灰石相晶体形态相似但支架孔隙率不同，显示出植入的大鼠MSCs在支持骨生成能力方面存在显著差异。
