Trinity Centre for Bioengineering, Trinity College Dublin, Ireland.
Ann Biomed Eng. 2010 Sep;38(9):2896-909. doi: 10.1007/s10439-010-0059-6. Epub 2010 May 11.
The objective of this study was to investigate the hypothesis that the application of dynamic compression following transforming growth factor-beta3 (TGF-beta3) induced differentiation will further enhance chondrogenesis of mesenchymal stem cells (MSCs). Porcine MSCs were encapsulated in agarose hydrogels and cultured in a chemically defined medium with TGF-beta3 (10 ng/mL). Dynamic compression (1 Hz, 10% strain, 1 h/day) was initiated at either day 0 or day 21 and continued until day 42 of culture; with TGF-beta3 withdrawn from some groups at day 21. Biochemical and mechanical properties of the MSC-seeded constructs were evaluated up to day 42. The application of dynamic compression from day 0 inhibited chondrogenesis of MSCs. This inhibition of chondrogenesis in response to dynamic compression was not observed if MSC-seeded constructs first underwent 21 days of chondrogenic differentiation in the presence of TGF-beta3. Spatial differences in sGAG accumulation in response to both TGF-beta3 stimulation and dynamic compression were observed within the constructs. sGAG release from the engineered construct into the surrounding culture media was also dependent on TGF-beta3 stimulation, but was not effected by dynamic compression. Continued supplementation with TGF-beta3 appeared to be a more potent chondrogenic stimulus than the application of 1 h of daily dynamic compression following cytokine initiated differentiation. In the context of cartilage tissue engineering, the results of this study suggest that MSC seeded constructs should be first allowed to undergo chondrogenesis in vitro prior to implantation in a load bearing environment.
本研究旨在验证以下假设，即转化生长因子-β3（TGF-β3）诱导分化后施加动态压缩可进一步增强间充质干细胞（MSCs）的软骨形成。猪 MSCs 被包裹在琼脂糖水凝胶中，并在含有 TGF-β3（10ng/mL）的化学定义培养基中培养。从第 0 天或第 21 天开始施加动态压缩（1Hz，10%应变，每天 1 小时），持续到第 42 天培养结束；第 21 天从一些组中去除 TGF-β3。直到第 42 天，评估 MSC 接种构建体的生物化学和机械性能。从第 0 天开始施加动态压缩会抑制 MSCs 的软骨形成。如果 MSC 接种构建体在 TGF-β3 存在下首先经历 21 天的软骨分化，则不会观察到对动态压缩的软骨形成抑制。在构建体中，对 TGF-β3 刺激和动态压缩的 sGAG 积累存在空间差异。工程构建体中 sGAG 向周围培养基中的释放也依赖于 TGF-β3 刺激，但不受动态压缩的影响。持续补充 TGF-β3 似乎比细胞因子诱导分化后每天施加 1 小时的动态压缩更能促进软骨形成。在软骨组织工程的背景下，本研究的结果表明，在植入承载负荷的环境之前，应首先允许 MSC 接种构建体在体外进行软骨形成。
