Yamamoto Ei, Kogawa Daisuke, Tokura Susumu, Hayashi Kozaburo
Biomechanics Laboratory, Department of Mechanical Engineering and Biomimetics, School of Biology-Oriented Science and Technology, Kinki University, Kinokawa, Wakayama 649-6493, Japan.
J Biomech. 2007;40(9):2063-70. doi: 10.1016/j.jbiomech.2006.10.007. Epub 2007 Mar 30.
In vitro tissue culture experiments were performed to study the biomechanical response of collagen fascicles to restressing after exposure to non-loaded condition. Collagen fascicles of approximately 300 microm in diameter were aseptically dissected from rabbit patellar tendons. They were cultured under no-load condition for 1 week, and then under a static stress of approximately 1.2 MPa for the subsequent 1 or 2 weeks. After culture, their mechanical properties were determined with a micro-tensile tester, and were compared to those of fascicles cultured under no-load condition and non-cultured, control fascicles. Tangent modulus and tensile strength of the non-loaded fascicles were significantly lower than those of the control fascicles at 1 week and gradually decreased thereafter. However, the modulus and strength were increased by restressing. After 2-week restressing, both parameters were significantly greater than those of the time-matched, non-loaded fascicles, although these values were still significantly lower than those of the control fascicles. That is, the application of stress after exposure to non-loaded condition suppressed the deterioration of the biomechanical properties of fascicles, although it did not improve. These results indicate that a short period of stressing is not sufficient for cultured collagen fascicles to completely recover their mechanical properties, if they are once exposed to no-stress condition even for a short period of time. These are similar to previous results observed in tendons and ligaments inside the body.
进行了体外组织培养实验，以研究胶原纤维束在暴露于无负荷状态后再施加应力时的生物力学反应。从兔髌腱中无菌解剖出直径约300微米的胶原纤维束。将它们在无负荷条件下培养1周，然后在约1.2兆帕的静态应力下培养接下来的1或2周。培养后，用微型拉伸试验机测定其力学性能，并与在无负荷条件下培养的纤维束以及未培养的对照纤维束的力学性能进行比较。无负荷纤维束的切线模量和拉伸强度在1周时显著低于对照纤维束，此后逐渐下降。然而，再施加应力后模量和强度增加。再施加应力2周后，这两个参数均显著高于同期的无负荷纤维束，尽管这些值仍显著低于对照纤维束。也就是说，在暴露于无负荷状态后施加应力可抑制纤维束生物力学性能的恶化，尽管不能使其恢复。这些结果表明，如果培养的胶原纤维束曾暴露于无应力状态哪怕很短时间，短时间的应力施加不足以使其完全恢复力学性能。这些结果与之前在体内肌腱和韧带中观察到的结果相似。
