Behravesh Esfandiar, Mikos Antonios G
Department of Bioengineering, Rice University, MS-142, P.O. Box 1892, Houston, Texas 77251-1892, USA.
J Biomed Mater Res A. 2003 Sep 1;66(3):698-706. doi: 10.1002/jbm.a.10003.
This study assesses the ability of biomimetic poly(propylene fumarate-co-ethylene glycol)-based hydrogels to sustain the differentiation of marrow stromal cells (MSCs) to the osteoblastic phenotype and to produce a mineralized matrix in vitro. Macroporous hydrogels based on poly(propylene fumarate-co-ethylene glycol) with and without covalently linked RGD cell-adhesive peptide were synthesized and seeded with rat MSCs suspended in media or in a type I collagen solution. Cells suspended in media were found to adhere to RGD-modified but not to unmodified hydrogels. Cells suspended in a collagen solution were entrapped after collagen gelation and proliferated independent of the peptide modification of the hydrogel. Hydrogel modification with RGD peptide was sufficient to allow for the adhesion and differentiation of MSCs to the osteoblastic phenotype in the presence of osteogenic culture supplements. MSCs seeded with a collagen gel onto RGD-modified macroporous hydrogels after 28 days of culture showed a significant increase in cell numbers, from 15,200 +/- 2,000 to 208,600 +/- 69,700 cells (p < 0.05). Moreover, significant calcium deposition was apparent after 28 days of culture in RGD-modified hydrogels for cells suspended in a collagen gel in comparison to cells suspended in media, 3.47 +/- 0.26 compared to 0.82 +/- 0.20 mg Ca(2+) per scaffold (p < 0.05). Confocal microscopy revealed that MSCs suspended in a collagen gel and cultured on RGD-modified hydrogels for 28 days were adhered to the surface of the hydrogel while MSCs suspended in a collagen gel and cultured on unmodified hydrogels were located within the pores of and not in direct contact with the hydrogel surface. The results demonstrate that these biomimetic hydrogels facilitate the adhesion and support the differentiation of MSCs to the osteoblastic phenotype in the presence of osteogenic culture media.
本研究评估了基于仿生聚（富马酸丙二醇酯 - 共 - 乙二醇）的水凝胶在体外维持骨髓基质细胞（MSCs）向成骨细胞表型分化并产生矿化基质的能力。合成了基于聚（富马酸丙二醇酯 - 共 - 乙二醇）且有无共价连接RGD细胞黏附肽的大孔水凝胶，并接种悬浮于培养基或I型胶原溶液中的大鼠MSCs。发现悬浮于培养基中的细胞可黏附于RGD修饰的水凝胶而非未修饰的水凝胶。胶原溶液中的细胞在胶原凝胶化后被包埋，并独立于水凝胶的肽修饰而增殖。在成骨培养补充剂存在的情况下，用RGD肽修饰水凝胶足以使MSCs黏附并向成骨细胞表型分化。培养28天后，接种胶原凝胶到RGD修饰的大孔水凝胶上的MSCs细胞数量显著增加，从15200±2000个细胞增加到208600±69700个细胞（p < 0.05）。此外，与悬浮于培养基中的细胞相比，在RGD修饰的水凝胶中培养28天后，悬浮于胶原凝胶中的细胞有明显的钙沉积，每支架分别为3.47±0.26与0.82±0.20 mg Ca(2+)（p < 0.05）。共聚焦显微镜显示，悬浮于胶原凝胶中并在RGD修饰的水凝胶上培养28天的MSCs黏附于水凝胶表面，而悬浮于胶原凝胶中并在未修饰的水凝胶上培养的MSCs位于水凝胶孔内且不与水凝胶表面直接接触。结果表明，这些仿生水凝胶在成骨培养基存在的情况下促进了MSCs的黏附，并支持其向成骨细胞表型分化。
