Osteoarthritis is a debilitating disease characterized by cartilage degradation and altered cartilage mechanical properties. Furthermore, it is well established that obesity is a primary risk factor for osteoarthritis. The purpose of this study was to investigate the influence of obesity on the mechanical properties of murine knee cartilage. Two-month old wild type mice were fed either a normal diet or a high fat diet for 16 weeks. Atomic force microscopy-based nanoindentation was used to quantify the effective indentation modulus of medial femoral condyle cartilage. Osteoarthritis progression was graded using the OARSI system. Additionally, collagen organization was evaluated with picrosirius red staining imaged using polarized light microscopy. Significant differences between diet groups were assessed using t tests with p < 0.05. Following 16 weeks of a high fat diet, no significant differences in OARSI scoring were detected. However, we detected a significant difference in the effective indentation modulus between diet groups. The reduction in cartilage stiffness is likely the result of disrupted collagen organization in the superficial zone, as indicated by altered birefringence on polarized light microscopy. Collectively, these results suggest obesity is associated with changes in knee cartilage mechanical properties, which may be an early indicator of disease progression.

骨关节炎是一种使人衰弱的疾病，其特征是软骨退化和软骨机械性能改变。此外，众所周知，肥胖是骨关节炎的主要危险因素。本研究的目的是调查肥胖对小鼠膝关节软骨力学性能的影响。给两个月大的野生型小鼠喂食正常饮食或高脂肪饮食 16 周。基于原子力显微镜的纳米压痕用于量化内侧股骨髁软骨的有效压痕模量。使用 OARSI 系统对骨关节炎进展进行分级。此外，使用偏光显微镜成像的天狼星红染色评估胶原组织。使用t评估饮食组之间的显着差异检验 p < 0.05。在高脂肪饮食 16 周后，未检测到 OARSI 评分的显着差异。然而，我们发现饮食组之间的有效压痕模量存在显着差异。软骨硬度的降低很可能是浅层胶原组织破坏的结果，如偏振光显微镜下双折射改变所表明的那样。总的来说，这些结果表明肥胖与膝关节软骨机械特性的变化有关，这可能是疾病进展的早期指标。