Mechanical Compatibility of Biomaterials evaluated by Culture System

在本实验中，我们开发了一个培养系统，以检查机械刺激对胶原凝胶标本涉及成纤维细胞的影响。在拉伸和压缩状态下，应变幅度设定为10%，频率为0.5Hz，每天24小时，持续1或2周。通过显微镜下的微拉伸试验，测定了试件和对照试件在静态条件下的弹性模量和最大应力等力学性能。结果发现，这两个指标的机械性能增加，根据在实验和对照标本的培养时间。实验中还发现，实验组的强化效果比对照组显著。在力学测试中，我们利用图像分析仪测量标记颗粒的位置，进一步测量了试件的应变分布。强化主要发生在试样的中心部位， ...更多信息 s的实现，而产生压应力的试样的两端的最小强化。机械刺激的影响程度因细胞类型而异。在骨髓基质细胞中，细胞产生的张应力非常强，即使是静态条件下的样本也会收缩得非常厉害，并且它们会从固定凝胶的不锈钢t形丝网上脱落。另一方面，L细胞产生的张应力很小，机械刺激的影响很小。在该模型中，将股骨-髌腱-胫骨标本固定在不锈钢保持器中并移植到背部皮肤下，施加人工重复拉伸应力。肌腱的最大强度没有减少，如果施加机械刺激，但在静态条件下的控制标本。因此，在活体中执行机械功能的结缔组织中，组织的命运受机械环境的支配。人工材料与活体组织的力学完整性是基于胶原与生物材料之间的强结合，而细胞尤其是成纤维细胞和成骨细胞在界面处产生的张应力可能使它们相互匹配，从而导致组织和材料之间的生物相容性差异。少

In this experiment, we developed a culture system to examine the effect of mechanical stimuli on the collagen gel specimen involving fibroblasts. The magnitude of strains were set to 10% in tension and compression, the frequency was 0.5Hz, 24 hours a day and last 1 or 2 weeks. The mechanical properties of elastic moduli and maximum stress of specimens after testing and the control specimens at static condition were measured by micro tensile testing under microscope. It was found that both indicators of mechanical properties increase in accordance with the culture time in experimental and control specimens. It also found that the strengthening of specimens were more significant in experimental group than control group In mechanical testing we further measure the strains distributions of spesimens by the use of the marker particles which locations were measured by image analyzes. The strenghtening was induced mainly on the central parts of the specimens where the tensile stress condition … More s were realized, whereas both ends of the specimens where compressive stress were generated were least strengthened. The degree of the effects of mechanical stimuli differ among the type of the cells. In bone marrow stromal cells, the tensile stresses generated by the cells were very strong and even the specimens in static conditions shrank very much and they detached from the stainless steel t wire mesh holding the gel. On the other hand, the tensile stress generated by the L cells were very small and very little effect of mechanical stimuli were observed.The in vivo experiments, which were the couterparts of the previous vitro experiments were developed. In this rat model in which a femora-patellar tendon-tibia specimen were fixed in a stainless steel holder and transplanted under the back skin, artificial repetitive tensile stress were applied. The maximum strength of the tendon did not decreased if the mechanical stimuli were applied, but the control specimens under static conditions did. Thus in the connective tissue which carried out mechanical functions in living body, the fate of the tissues is governed by the mechanical environment. It also suggests that the mechanical integrity of the artificial materials and the living tissue is based on the strong binding between collagen and biomaterials, and since the cells especially fibroblasts and osteoblasts generate tensile stress which may datatch them at the interface, it may result in the differences in biocompatibilty among the tissues and materials. Less