Yang L, Tsai C M, Hsieh A H, Lin V S, Akeson W H, Sung K L
Department of Orthopaedics, University of California, San Diego, La Jolla 92093-0412, USA.
J Orthop Res. 1999 Sep;17(5):755-62. doi: 10.1002/jor.1100170521.
Fibroblasts embedded in the amorphous healing tissue matrix of ligaments migrate into damaged sites during the inflammatory process that precedes the formation of new connective tissue after ligament injury. Cell motility involved in this migration is strongly influenced by cellular adhesion to proteins of the extracellular matrix. The adhesion mechanism of interest in this study is the attachment of fibroblasts from the anterior cruciate and medial collateral ligaments to types I and III collagen, two fibrillar collagens secreted by fibroblasts during tissue repair. Types I and III collagen constitute a major portion of these ligaments and are assembled by fibroblasts into long cable-like fibrils in the extracellular space. In this study, a micropipette aspiration technique was used to measure the force required to separate fibroblasts of the anterior cruciate and medial collateral ligaments from substrates composed of type I or III collagen, each at a concentration of 2 or 5 microg/ml. Approximately 1,200 fibroblasts from the anterior cruciate ligament and 1,600 from the medial collateral ligament were used, and the adhesion force and area of these cells were determined. Fibroblasts from the anterior cruciate ligament exhibited greater adhesion force than did those from the medial collateral ligament for all concentrations of types I and III collagen. In addition, the adhesiveness of fibroblasts from both ligaments was dependent on seeding time for all experimental conditions. To determine the adhesiveness per unit area, defined here as the adhesion strength, the adhesion force was normalized by the adhesion area. At early seeding times (15-45 minutes), fibroblasts from the anterior cruciate ligament exhibited greater adhesion strength on surfaces coated with type-I collagen than did those from the medial collateral ligament. However, for both collagen substrates, adhesion strength for fibroblasts from the anterior cruciate ligament decreased with seeding time whereas that for fibroblasts from the medial collateral ligament remained relatively constant for all seeding periods (15-75 minutes).
在韧带损伤后新结缔组织形成之前的炎症过程中，嵌入韧带无定形愈合组织基质中的成纤维细胞会迁移到受损部位。这种迁移过程中涉及的细胞运动受到细胞与细胞外基质蛋白质粘附的强烈影响。本研究感兴趣的粘附机制是前交叉韧带和内侧副韧带中的成纤维细胞与I型和III型胶原蛋白的附着，这两种纤维状胶原蛋白是成纤维细胞在组织修复过程中分泌的。I型和III型胶原蛋白构成了这些韧带的主要部分，并由成纤维细胞在细胞外空间组装成长的索状纤维。在本研究中，使用微量移液器抽吸技术来测量将前交叉韧带和内侧副韧带的成纤维细胞与由I型或III型胶原蛋白组成的底物分离所需的力，每种胶原蛋白的浓度为2或5微克/毫升。使用了大约1200个来自前交叉韧带的成纤维细胞和1600个来自内侧副韧带的成纤维细胞，并测定了这些细胞的粘附力和面积。对于所有浓度的I型和III型胶原蛋白，前交叉韧带的成纤维细胞比内侧副韧带的成纤维细胞表现出更大的粘附力。此外，在所有实验条件下，来自两条韧带的成纤维细胞的粘附性都取决于接种时间。为了确定单位面积的粘附性，在此定义为粘附强度，将粘附力除以粘附面积进行归一化。在早期接种时间（15 - 45分钟），前交叉韧带的成纤维细胞在涂有I型胶原蛋白的表面上比内侧副韧带的成纤维细胞表现出更大的粘附强度。然而，对于两种胶原蛋白底物，前交叉韧带的成纤维细胞的粘附强度随接种时间而降低，而内侧副韧带的成纤维细胞的粘附强度在所有接种时间段（15 - 75分钟）内保持相对恒定。
