Yamamoto Ei, Iwanaga Wataru, Miyazaki Hiroshi, Hayashi Kozaburo
Department of Mechanical Engineering, School of Biology-Oriented Science and Technology, Kinki University, Wakayama, Japan.
J Biomech Eng. 2002 Feb;124(1):85-93. doi: 10.1115/1.1427924.
In-vitro tissue culture experiments were performed to study the effects of static stress on the mechanical properties of collagen fascicles obtained from the rabbit patellar tendon. After collagen fascicles having the diameter of approximately 300 microm were cultured for 1 and 2 wk under static stress between 0 and 3 MPa, their mechanical properties and crimp morphology were determined using a micro-tensile tester and a light microscope, respectively. The tensile strength and tangent modulus of the fascicles were significantly decreased by culture under no load compared to control fascicles. A statistically significant correlation, which was described by a quadratic curve, was observed between applied stress and tensile strength. The maximum tensile strength (16.7 MPa) was obtained at the applied stress of 1.2 MPa; the strength was within a range of control values. There was a similar correlation between applied stress and tangent modulus, and the modulus was maintained at control level under 1.3 MPa stress. The stress of 1.2 to 1.3 MPa is equivalent to approximately 50 percent of the peak stress developed in the intact rabbit patellar tendon by running. Strain at failure of cultured collagen fascicles was negatively correlated with applied stress, and that at 1.2 to 1.3 MPa stress was almost the same as the control value. Crimp morphology in the fascicles cultured under about 1.2 MPa stress was similar to that in control fascicles. These results indicate that cultured collagen fascicles change the mechanical properties and structure in response to static tensile stress. In addition, their mechanical properties and structure are maintained at control level if the static stress of 50 percent of in-vivo peak stress is applied.
进行体外组织培养实验，以研究静态应力对从兔髌腱获取的胶原束力学性能的影响。将直径约为300微米的胶原束在0至3兆帕的静态应力下培养1周和2周后，分别使用微拉伸测试仪和光学显微镜测定其力学性能和卷曲形态。与对照胶原束相比，无负载培养使胶原束的拉伸强度和切线模量显著降低。观察到施加应力与拉伸强度之间的拉伸强度之间存在由二次曲线描述的统计学显著相关性。在1.2兆帕的施加应力下获得最大拉伸强度（16.7兆帕）；该强度在对照值范围内。施加应力与切线模量之间存在类似的相关性，并且在1.3兆帕应力下模量维持在对照水平。1.2至1.3兆帕的应力相当于完整兔髌腱在奔跑时产生的峰值应力的约50%。培养的胶原束断裂应变与施加应力呈负相关，在1.2至1.3兆帕应力下的断裂应变与对照值几乎相同。在约1.2兆帕应力下培养的胶原束中的卷曲形态与对照胶原束中的相似。这些结果表明，培养的胶原束会响应静态拉伸应力而改变其力学性能和结构。此外，如果施加体内峰值应力50%的静态应力，其力学性能和结构会维持在对照水平。
