Neovascularization and bone regeneration by implantation of autologous bone marrow mononuclear cells for osteonecrosis

本研究观察了自体骨髓单个核细胞（BM-MNCs）移植是否能促进兔股骨骨缺损的骨髓新生血管和骨再生。制备了碱性成纤维细胞生长因子（bFGF）明胶微球，用于bFGF的控释。为了评价植入BM-MNCs的体内效应，我们在兔股骨内侧髁建立骨缺损，并将5 × 10^6个荧光标记的自体BM-MNCs与含有10 μg bFGF的明胶微球一起植入去端胶原凝胶支架中。以Atelocollagen凝胶为支架材料，将Col、Col + 5 × 10^6 BM-MNCs、Col + 10 μg bFGF、Col + 5 × 10^6 BM-MNCs + 10 μg bFGF 4个实验组植入缺损区。自体BM-MNCs表达CD 31，一种内皮谱系细胞标志物，并在植入后两周在植入部位诱导有效的新生血管形成。与其他组相比，Col + BM-MNCs + bFGF中的毛细血管密度显著较大。这种组合也在8周后增强了骨缺损的再生，其程度明显大于BM-MNCs或bFGF本身。总之，这些发现表明BM-MNCs和bFGF明胶水凝胶的组合增强了新血管形成和骨诱导能力，导致骨再生。

We examined whether transplantation of autologous bone marrow mononuclear cells (BM-MNCs) can augment neovasculalization and bone regeneration of bone marrow in femoral bone defects of rabbits. Gelatin microspheres containing basic fibroblast growth factor (bFGF) were prepared for the controlled release of bFGF. To evaluate the in vivo effect of implanted BM-MNCs, we created bone defects in the rabbit medial femoral condyle, and implanted into them 5 × 10^6 fluorescent-labeled autologous BM-MNCs together with gelatin microspheres containing 10 μg bFGF on an atelocollagen gel scaffold. The four experimental groups, which were Atelocollagen gel (Col), Col + 5 × 10^6 BM-MNCs, Col + 10 μg bFGF, and Col + 5 × 10^6 BM-MNCs + 10 μg bFGF, were implanted into the sites of the prepared defects using Atelocollagen gel as a scaffold. The autologous BM-MNCs expressed CD31, an endothelial lineage cell marker, and induced efficient neovascularization at the implanted site two weeks after implantation. Capillary density in Col + BM-MNCs + bFGF was significantly large compared with other groups. This combination also enhanced regeneration of the bone defect after eight weeks to a significantly greater extent than either BM-MNCs or bFGF on their own. In summary, these findings demonstrate that a combination of BM-MNCs and bFGF gelatin hydrogel enhance the neovascularization and the osteoinductive ability, resulting in bone regeneration.