Department of Public Health, Health Management and Policy, Nara Medical University School of Medicine, Kashihara, Nara 634-8521, Japan.
J Tissue Eng Regen Med. 2010 Jul;4(5):404-11. doi: 10.1002/term.259.
We previously reported a new cell transplantation method in which mesenchymal stem cells (MSCs) were cultured as cell sheets. The cultured MSC sheets showed high alkaline phosphatase (ALP) activities and osteocalcin (OC) contents. In the present study, we transplanted such sheets by injection to assess whether the injectable MSC sheets could form bone tissue at subcutaneous sites. At 4 weeks after the subcutaneous injection, the injected areas showed hard mass formation. Each mass consisted of newly formed bone, as evaluated by radiographic, histological and gene expression analyses as well as three-dimensional computed tomography (3D-CT). Histological analyses revealed extracellular bone matrix together with osteocytes and active osteoblasts. Real-time PCR analyses showed high ALP and OC mRNA expressions. We also injected the cell sheets into dead bone to determine whether the lost osteogenic potential could be rescued, and histological analyses revealed that the injected cell sheets supplied osteogenic potential to the dead bone. The present study clearly indicates that osteogenic MSC sheets can be transplanted via injection through a needle and that bone formation results in the injected areas. Owing to its usage of a needle for fabrication of in vivo bone tissue, this injection method can be applied as a minimally invasive approach for hard tissue reconstruction.
我们之前报道了一种新的细胞移植方法，即将间充质干细胞（MSCs）培养成细胞片。培养的 MSC 片表现出高碱性磷酸酶（ALP）活性和骨钙素（OC）含量。在本研究中，我们通过注射移植了这些细胞片，以评估可注射的 MSC 片是否能在皮下部位形成骨组织。在皮下注射后 4 周，注射部位出现了坚硬的肿块形成。通过影像学、组织学和基因表达分析以及三维计算机断层扫描（3D-CT）评估，每个肿块都由新形成的骨组成。组织学分析显示，有细胞外骨基质，还有骨细胞和活跃的成骨细胞。实时 PCR 分析显示 ALP 和 OC mRNA 表达水平较高。我们还将细胞片注入死骨中，以确定是否可以挽救失去的成骨潜能，组织学分析显示，注射的细胞片为死骨提供了成骨潜能。本研究清楚地表明，成骨 MSC 片可以通过注射用的针头进行移植，并且注射部位会形成骨组织。由于该注射方法使用针头来制造体内骨组织，因此它可作为一种微创方法应用于硬组织重建。
