Superficial cartilage defect is an important factor that causes osteoarthritis. Therefore, it is very important to investigate the influence of superficial cartilage defects on its surface morphology and mechanical properties. In this study, the knee joint cartilage samples of adult pig were prepared, which were treated by enzymolysis with chymotrypsin and physical removal with electric friction pen, respectively. Normal cartilage and surface treated cartilage were divided into five groups: control group (normal cartilage group), chymotrypsin immersion group, chymotrypsin wiping group, removal 10% group with electric friction pen, and removal 20% group with electric friction pen. The surface morphology and structure of five groups of samples were characterized by laser spectrum confocal microscopy and environmental field scanning electron microscopy, and the mechanical properties of each group of samples were evaluated by tensile tests. The results show that the surface arithmetic mean height and fracture strength of the control group were the smallest, and the fracture strain was the largest. The surface arithmetic mean height and fracture strength of the removal 20% group with electric friction pen were the largest, and the fracture strain was the smallest. The surface arithmetic mean height, fracture strength and fracture strain values of the other three groups were all between the above two groups, but the surface arithmetic mean height and fracture strength of the removal 10% group with electric friction pen, the chymotrypsin wiping group and the chymotrypsin soaking group decreased successively, and the fracture strain increased successively. In addition, we carried out a study on the elastic modulus of different groups, and the results showed that the elastic modulus of the control group was the smallest, and the elastic modulus of the removal 20% group with electric friction pen was the largest. The above study revealed that the defect of the superficial area of cartilage changed its surface morphology and structure, and reduced its mechanical properties. The research results are of great significance for the prevention and repair of cartilage injury.
软骨浅表区缺失是引发骨关节炎的一个重要因素，探究软骨浅表区缺损对其表面形貌及力学性能的影响非常重要。本文取成年猪膝关节软骨，分别采用糜蛋白酶酶解处理和电摩擦笔物理去除方法，对其表面进行处理，将正常软骨和表面处理后的软骨分为五组：对照组（正常软骨组）、糜蛋白酶浸泡组、糜蛋白酶擦拭组、电摩擦笔去除10%组、电摩擦笔去除20%组。使用激光光谱共聚焦显微镜和环境场扫描电子显微镜对五组样本进行表面形貌及结构表征，并开展拉伸实验评估每组样本力学性能。研究表明，对照组的表面算术平均高度最小、断裂强度最小、断裂应变最大；电摩擦笔去除20%组的表面算术平均高度最大、断裂强度最大、断裂应变最小，其余三组表面算术平均高度、断裂强度和断裂应变值均介于上述两组之间，其中电摩擦笔去除10%组、糜蛋白酶擦拭组、糜蛋白酶浸泡组表面算术平均高度和断裂强度依次降低，断裂应变依次增大。此外，课题组对不同组弹性模量展开研究，结果表明，对照组弹性模量最小，电摩擦笔去除20%组弹性模量最大。以上研究发现，软骨浅表区的缺损改变了其表面形貌和结构，降低了其力学性能。本文研究成果或对软骨损伤预防及缺损修复具有重要意义。.
Keywords: Articular cartilage; Mechanical properties; Superficial injury of cartilage; Surface topography.