Leigh Diane R, Abreu Eduardo L, Derwin Kathleen A
Department of Biomedical Engineering, Orthopaedic Research Center, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA.
J Orthop Res. 2008 Oct;26(10):1306-12. doi: 10.1002/jor.20650.
Immobilization of the tendon and ligament has been shown to result in a rapid and significant decrease in material properties. It has been proposed that tissue degradation leading to tendon rupture or pain in humans may also be linked to mechanical unloading following focal tendon injury. Hence, understanding the remodeling mechanism associated with mechanical unloading has relevance for the human conditions of immobilization (e.g., casting), delayed repair of tendon ruptures, and potentially overuse injuries as well. This is the first study to investigate the time course of gene expression changes associated with tissue harvest and mechanical unloading culture in an explant model. Rat tail tendon fascicles were harvested and placed in culture unloaded for up to 48 h and then evaluated using qRT-PCR for changes in two anabolic and four catabolic genes at 12 time points. Our data demonstrates that Type I Collagen, Decorin, Cathepsin K, and MMP2 gene expression are relatively insensitive to unloaded culture conditions. However, changes in both MMP3 and MMP13 gene expression are rapid, dramatic, sustained, and changing during at least the first 48 h of unloaded culture. This data will help to further elucidate the mechanism for the loss of mechanical properties associated with mechanical unloading in tendon.
已证明肌腱和韧带的固定会导致材料特性迅速且显著下降。有人提出，导致人类肌腱断裂或疼痛的组织退化也可能与局部肌腱损伤后的机械卸载有关。因此，了解与机械卸载相关的重塑机制对于人类固定（如石膏固定）、肌腱断裂延迟修复以及潜在的过度使用损伤等情况具有重要意义。这是第一项研究在体外模型中与组织采集和机械卸载培养相关的基因表达变化时间进程的研究。采集大鼠尾腱束并置于无负荷培养中长达48小时，然后在12个时间点使用qRT-PCR评估两个合成代谢基因和四个分解代谢基因的变化。我们的数据表明，I型胶原蛋白、核心蛋白聚糖、组织蛋白酶K和MMP2基因表达对无负荷培养条件相对不敏感。然而，MMP3和MMP13基因表达的变化迅速、显著、持续，并且至少在无负荷培养的前48小时内不断变化。这些数据将有助于进一步阐明与肌腱机械卸载相关的力学性能丧失的机制。
