Cowan Catherine M, Aghaloo Tara, Chou Yu-Fen, Walder Benjamin, Zhang Xinli, Soo Chia, Ting Kang, Wu Benjamin
Department of Bioengineering, University of California, Los Angeles, California 90095, USA.
Tissue Eng. 2007 Mar;13(3):501-12. doi: 10.1089/ten.2006.0141.
Numerous growth factors, peptides, and small molecules are being developed for bone tissue engineering. The optimal dosing, stability, and bioactivity of these biological molecules are likely influenced by the carrier biomaterial. Efficient evaluation of various formulations will require objective evaluation of in vitro culture systems and in vivo regeneration models. The objective of this paper is to examine the utility of microcomputed tomography (microCT) over conventional techniques in the evaluation of the bone morphogenetic protein-2 (BMP-2) dose response effect in a three-dimensional (3D) in vitro culture system and in an established calvarial defect model. Cultured MC3T3-E1 osteoblasts displayed increased cellular density, extracellular matrix (ECM) production, and mineralization on 3D poly(lactic-co-glycolic acid) (PLGA) scaffolds in a BMP-2 dose dependent manner. MicroCT revealed differences in shape and spatial organization of mineralized areas, which would not have been possible through conventional alizarin red staining alone. Additionally, BMP-2 (doses of 30 to 240 ng/mm(3)) was grafted into 5 mm critical sized rat calvarial defects, where increased bone regeneration was observed in a dose dependent manner, with higher doses of BMP-2 inducing greater bone area, volume, and density. The data revealed the utility of microCT analysis as a beneficial addition to existing techniques for objective evaluation of bone tissue engineering and regeneration.
目前正在开发多种生长因子、肽和小分子用于骨组织工程。这些生物分子的最佳剂量、稳定性和生物活性可能受载体生物材料的影响。对各种制剂进行有效评估需要对体外培养系统和体内再生模型进行客观评价。本文的目的是研究在三维（3D）体外培养系统和已建立的颅骨缺损模型中，微计算机断层扫描（microCT）相对于传统技术在评估骨形态发生蛋白-2（BMP-2）剂量反应效应方面的实用性。培养的MC3T3-E1成骨细胞在3D聚乳酸-乙醇酸共聚物（PLGA）支架上以BMP-2剂量依赖性方式表现出细胞密度增加、细胞外基质（ECM）产生增加和矿化增加。MicroCT揭示了矿化区域在形状和空间组织上的差异，这仅通过传统的茜素红染色是不可能实现的。此外，将BMP-2（剂量为30至240 ng/mm(3)）植入5 mm临界大小的大鼠颅骨缺损处，观察到骨再生以剂量依赖性方式增加，较高剂量的BMP-2诱导更大面积、体积和密度的骨形成。数据表明，microCT分析作为现有技术的有益补充，可用于骨组织工程和再生的客观评估。
