Gründer Tatiana, Gaissmaier Christoph, Fritz Jürgen, Stoop Reinout, Hortschansky Peter, Mollenhauer Jürgen, Aicher Wilhelm K
TETEC AG, Aspenhaustrasse 25, 72770 Reutlingen, Germany.
Osteoarthritis Cartilage. 2004 Jul;12(7):559-67. doi: 10.1016/j.joca.2004.04.001.
For autologous chondrocyte transplantation (ACT) chondrocytes are expanded in vitro. During expansion these cells may dedifferentiate. This change in phenotype is characterized by a raised expression of type I collagen and a decrease in type II collagen expression. Since high expression of type II collagen is of central importance for the properties of hyaline cartilage, we investigated if the growth factor bone morphogenetic protein-2 (BMP-2) may modulate the chondrogenic phenotype in monolayer cell cultures and in three-dimensional culture systems.
Chondrocytes from articular knee cartilage of 11 individuals (average age: 39.8 years) with no history of joint disease were isolated and seeded either in monolayer cultures or embedded in alginate beads in presence or absence of human recombinant BMP-2 (hr-BMP-2). Then, cells were harvested and analysis of the chondrogenic phenotype was performed using quantitative RT-PCR, immunocytochemistry and ELISA.
Addition of BMP-2 to chondrocytes expanded in two-dimensional (2D) cultures during the first subculture (P1) had no effect on mRNA amounts encoding type II collagen and interleukin-1beta (IL-1beta). In contrast, seeding chondrocytes in three-dimensional (3D) alginate cultures raised type II collagen expression significantly and addition of BMP-2 enhanced this effect.
We conclude that chondrocytes during expansion for ACT may benefit from BMP-2 activation only when seeded in an appropriate 3D culture system.
在自体软骨细胞移植（ACT）中，软骨细胞需在体外进行扩增。在扩增过程中，这些细胞可能会发生去分化。这种表型变化的特征是I型胶原蛋白表达升高，II型胶原蛋白表达降低。由于II型胶原蛋白的高表达对于透明软骨的特性至关重要，我们研究了生长因子骨形态发生蛋白-2（BMP-2）是否可以在单层细胞培养和三维培养系统中调节软骨形成表型。
从11名无关节疾病史的个体（平均年龄：39.8岁）的膝关节软骨中分离软骨细胞，并将其接种于单层培养物中，或在存在或不存在重组人BMP-2（hr-BMP-2）的情况下包埋于藻酸盐珠中。然后，收获细胞，并使用定量RT-PCR、免疫细胞化学和ELISA对软骨形成表型进行分析。
在第一次传代培养（P1）期间，向二维（2D）培养中扩增的软骨细胞添加BMP-2，对编码II型胶原蛋白和白细胞介素-1β（IL-1β）的mRNA量没有影响。相反，将软骨细胞接种于三维（3D）藻酸盐培养中可显著提高II型胶原蛋白表达，添加BMP-2可增强这种效果。
我们得出结论，在ACT扩增过程中的软骨细胞，只有接种于合适的三维培养系统中时，才可能从BMP-2激活中受益。
