Dennis J E, Haynesworth S E, Young R G, Caplan A I
Department of Biology, Case Western Reserve University, Cleveland, OH 44106.
Cell Transplant. 1992;1(1):23-32. doi: 10.1177/096368979200100106.
Cultured-expanded rat marrow-derived mesenchymal cells differentiate into osteoblasts when combined with a porous calcium phosphate delivery vehicle and subsequently implanted in vivo. In this study, the effects of ceramic pretreatment with the cell-binding proteins fibronectin and laminin on the osteogenic expression of marrow-derived mesenchymal cells were assessed by scanning electron microscopy, [3H]-thymidine-labeled cell quantitation, and histological evaluation of bone formation. Scanning electron microscopic observations showed that marrow-derived mesenchymal cells rapidly spread and attach to both fibronectin- or laminin-adsorbed ceramic surfaces but retain a rounded morphology on untreated ceramic surfaces. Quantitation of [3H]-thymidine labeled cells demonstrated that laminin and fibronectin preadsorbed ceramics retain approximately double the number of marrow-derived mesenchymal cells than do untreated ceramics harvested 1 wk postimplantation. Histological observations indicate that the amount of time required to first detect osteogenesis was shortened significantly by pretreatment of the ceramic with either fibronectin or laminin. Fibronectin- and laminin-coated ceramic composite samples were observed to contain bone within 2 wk postimplantation, while in untreated ceramic the earliest observation of bone was at 4 wk postimplantation. A comparison was made of the initial cell-loading, in vivo cell retention characteristics, and rate of osteogenesis initiation of marrow-derived mesenchymal cells on two types of ceramic with different pore structure and chemical composition, with and without preadsorption with fibronectin or laminin. "Biphasic" ceramics contain randomly distributed pores 200-400 microns in diameter, and "coral-based" ceramics have continuous pores of approximately 200 microns in diameter. Laminin or fibronectin preadsorption significantly increases the number of cells retained in all ceramic test groups by day 7 postimplantation. In addition, by day 7 postimplantation, the biphasic ceramics retain a significantly greater number of cells for all test groups than do coral-based ceramics. The biphasic ceramics consistently have more specimens positive for bone with the identical cell-loading conditions used throughout this study. These results indicate that the retention of cells within the ceramic is an important factor for optimization of marrow mesenchymal cell initiated bone formation. The retention of cells within ceramics is augmented by the adsorption of the cell-binding proteins laminin and fibronectin, but this effect varies depending on ceramic pore structure and/or chemical composition.
当与多孔磷酸钙递送载体结合并随后植入体内时，培养扩增的大鼠骨髓间充质细胞可分化为成骨细胞。在本研究中，通过扫描电子显微镜、[3H] - 胸腺嘧啶核苷标记细胞定量以及骨形成的组织学评估，来评价用细胞结合蛋白纤连蛋白和层粘连蛋白对陶瓷进行预处理对骨髓间充质细胞成骨表达的影响。扫描电子显微镜观察显示，骨髓间充质细胞能迅速铺展并附着于纤连蛋白或层粘连蛋白吸附的陶瓷表面，但在未处理的陶瓷表面上保持圆形形态。[3H] - 胸腺嘧啶核苷标记细胞的定量分析表明，层粘连蛋白和纤连蛋白预吸附的陶瓷在植入后1周收获时，保留的骨髓间充质细胞数量约为未处理陶瓷的两倍。组织学观察表明，用纤连蛋白或层粘连蛋白对陶瓷进行预处理可显著缩短首次检测到骨生成所需的时间。观察到纤连蛋白和层粘连蛋白包被的陶瓷复合样品在植入后2周内含有骨组织，而在未处理的陶瓷中最早在植入后4周观察到骨组织。对两种具有不同孔隙结构和化学成分的陶瓷（有无纤连蛋白或层粘连蛋白预吸附）上骨髓间充质细胞的初始细胞接种量、体内细胞保留特性和成骨起始速率进行了比较。“双相”陶瓷含有直径为200 - 400微米的随机分布孔隙，“珊瑚基”陶瓷具有直径约200微米的连续孔隙。层粘连蛋白或纤连蛋白预吸附在植入后第7天显著增加了所有陶瓷测试组中保留的细胞数量。此外，在植入后第7天，对于所有测试组，双相陶瓷保留的细胞数量显著多于珊瑚基陶瓷。在本研究中使用相同的细胞接种条件下，双相陶瓷始终有更多的骨阳性标本。这些结果表明，细胞在陶瓷内的保留是优化骨髓间充质细胞起始骨形成的一个重要因素。细胞结合蛋白层粘连蛋白和纤连蛋白的吸附增加了细胞在陶瓷内的保留，但这种效果因陶瓷孔隙结构和/或化学成分而异。
