Stem Cell and Mechanobiology Laboratory, Department of Biomedical Engineering, College of Engineering, University of Miami, Coral Gables, Florida 33146-0621, USA.
J Orthop Res. 2011 Nov;29(11):1634-41. doi: 10.1002/jor.21430. Epub 2011 Apr 11.
Research has shown that mechanical loading affects matrix biosynthesis of intervertebral disc (IVD) cells; however, the pathway(s) to this effect is currently unknown. Cellular matrix biosynthesis is an energy demanding process. The objective of this study was to investigate the effects of static and dynamic compressive loading on energy metabolism of IVD cells. Porcine annulus fibrosus (AF) and nucleus pulposus (NP) cells seeded in 2% agarose were used in this experiment. Experimental groups included 15% static compression and 0.1 and 1 Hz dynamic compression at 15% strain magnitude for 4 h. ATP, lactate, glucose, and nitric oxide (NO) contents in culture media, and ATP content in cell-agarose construct were measured using biochemical assays. While the total ATP content of AF cells was promoted by static and dynamic loading, only 1 Hz dynamic loading increased total ATP content of NP cells. Increases in lactate production and glucose consumption of AF cells suggest that ATP production via glycolysis is promoted by dynamic compression. ATP release and NO production of AF and NP cells were significantly increased by dynamic loading. Thus, this study clearly illustrates that static and dynamic compressive loading affect IVD cell energy production while cellular responses to mechanical loading were both cell type and compression type dependent.
研究表明，机械加载会影响椎间盘（IVD）细胞的基质生物合成；然而，目前尚不清楚其作用途径。细胞基质生物合成是一个耗能过程。本研究旨在探讨静态和动态压缩加载对 IVD 细胞能量代谢的影响。本实验使用在 2%琼脂糖中接种的猪纤维环（AF）和髓核（NP）细胞。实验组包括 15%静态压缩和 0.1 和 1 Hz 的动态压缩，应变幅度为 15%，持续 4 小时。使用生化分析测量培养基中的 ATP、乳酸、葡萄糖和一氧化氮（NO）含量以及细胞-琼脂糖构建体中的 ATP 含量。虽然静态和动态加载均促进了 AF 细胞的总 ATP 含量，但只有 1 Hz 的动态加载增加了 NP 细胞的总 ATP 含量。AF 细胞中乳酸生成和葡萄糖消耗的增加表明，糖酵解途径促进了 ATP 的生成。动态加载显著增加了 AF 和 NP 细胞的 ATP 释放和 NO 产生。因此，本研究清楚地表明，静态和动态压缩加载会影响 IVD 细胞的能量产生，而细胞对机械加载的反应既依赖于细胞类型，也依赖于压缩类型。
