Periodontal tissue regeneration by transplantation of own bone marrow mesenchymal stem cells

为了阐明移植后间充质干细胞（MSCs）的性能，我们培养了绿色荧光蛋白（GFP）转导的MSCs，并将其与终浓度为2 × 10^7个细胞/ml的atelocolagen混合，并将其移植到犬的实验性III类缺陷中。gfp转导的MSCs移植1个月后，免疫组化结果显示gfp阳性细胞遍布缺损的整个区域。骨水泥母细胞、再生骨的成骨细胞和骨细胞以及再生牙周韧带的成纤维细胞均呈gfp阳性。这些结果表明，部分移植的间充质干细胞能够存活，并向牙周组织细胞分化，释放多种细胞因子，促进牙周组织再生。另一项动物研究，MSCs移植于慢性牙周缺损模型，beagle犬的III类缺损伴炎症，在牙骨质再生方面的结果比对照组好得多。MSCs移植后2周，虽然骨再生尚未形成，但几乎所有脱落的根表面骨桥蛋白（OPN）均呈阳性。靠近根表面，沿表面排列有卵圆形细胞。未见上皮细胞侵袭。另一方面，对照组根表面未见免疫反应。上皮组织侵入分叉区顶部。这些结果表明，在根表面附近移植MSCs可能在早期分化为成骨水泥细胞，促进新骨水泥的形成。这些动物实验证明了骨髓间充质干细胞移植治疗牙周组织再生的潜力。

To elucidate the performance of mesenchymal stem cells (MSCs) after transplantation, green fluorescent protein (GFP)-transduced MSCs were cultured and mixed with Atelocollagen at final concentration of 2x10^7 cells/ml and were auto-transplanted into experimental class III defects in the dogs. One month after GFP-transduced MSCs transplantation, immunohistochemical results showed that GFP-positive cells were present in the whole area of the defects. Cementoblasts arranged along the denuded surface, osteoblasts and osteocytes of regenerated bone, and fibroblasts of the regenerated periodontal ligament were GFP-positive. These findings suggested that some transplanted MSCs survive, differentiate into periodontal tissue cells and release various kind of cytokines, all of which promote periodontal tissue regeneration.Another animal study, MSCs transplantation in chronic periodontal defects model, class III defects with inflammation in beagle dogs, showed much better results concerning cementum regeneration than control. 2 weeks after MSCs transplantation, although bone regeneration was not formed yet, almost all denuded root surface was osteopontin (OPN) positive. Adjacent to the root surface, oval shaped like cells were arranged along the surface. Epithelial cell invasion was not observed. On the other hand, in control group, immunoreaction was not observed on root surface. Epithelial tissue invaded into the top of furcation area. These findings indicated that transplantation of MSCs near the root surface might differentiate into cementblasts at early stage and enhance new cementum formation.These animal studies demonstrated the therapeutic potential of bone marrow MSCs transplantation for periodontal tissue regeneration.