Osteoarthritis (OA) is a chronic and complicated degenerative disorder of joints, including several phenotypes. Type 2 diabetes mellitus (T2DM) is one of the major causes of OA. However, few studies on the mechanical behavior of diabetic cartilages have been conducted. This study evaluated the microstructural, compositional, and mechanical properties of healthy and diabetic rat cartilages using scanning electronic microscopy, X-ray energy spectroscopy, histology staining, and microindentation tests. Our results indicated that the diabetic cartilages had a significantly higher elastic modulus and similar permeability (95%CI: 3.72–8.56 MPa and 3.16×10–1.83×10 mm/N·s) compared to the healthy cartilages (95%CI: 0.741–3.58 MPa and 3.15×10–1.14×10 mm/N·s). Their stress relaxation behaviors were similar regardless of the loading rate except for the stretching parameter under the fast loading. Furthermore, the stress relaxation behaviors of the diabetic cartilages were significantly affected by the loading rate, especially the equilibrium force ratio and time constant. These mechanical outcomes could be attributed to the increase of fibril diameters and calcium aggregation in the cartilage. This study deepens our understanding of how T2DM might facilitate OA in cartilages, which could contribute to the development of more scientific diagnosis and therapies for patients with diabetes.

中文翻译：

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2型糖尿病对软骨微观结构、成分和机械性能的影响

骨关节炎（OA）是一种慢性、复杂的关节退行性疾病，包括多种表型。 2 型糖尿病（T2DM）是 OA 的主要原因之一。然而，关于糖尿病软骨机械行为的研究很少。本研究使用扫描电子显微镜、X 射线能谱、组织学染色和显微压痕测试评估了健康和糖尿病大鼠软骨的微观结构、成分和机械特性。我们的结果表明，与健康软骨（95%CI：0.741）相比，糖尿病软骨具有显着更高的弹性模量和相似的渗透性（95%CI：3.72–8.56 MPa 和 3.16×10–1.83×10 mm/N·s） –3.58 MPa 和 3.15×10–1.14×10 mm/N·s）。除了快速加载下的拉伸参数之外，无论加载速率如何，它们的应力松弛行为都相似。此外，糖尿病软骨的应力松弛行为受到加载速率的显着影响，尤其是平衡力比和时间常数。这些机械结果可归因于原纤维直径的增加和软骨中钙的聚集。这项研究加深了我们对 T2DM 如何促进软骨 OA 的理解，这可能有助于为糖尿病患者开发更科学的诊断和治疗方法。