Gao Jiazi, Ren Pengling, Gong He
Department of Engineering Mechanics, Nanling Campus, Jilin University, Changchun, China.
Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
Front Bioeng Biotechnol. 2023 Jan 23;11:1080241. doi: 10.3389/fbioe.2023.1080241. eCollection 2023.
This study aimed to investigate the morphological and mechanical changes in articular cartilage and subchondral bone during spontaneous hip osteoarthritis in guinea pigs. Hip joints of guinea pigs were investigated at 1, 3, 6, and 9 months of age (hereafter denoted as 1 M, 3 M, 6 M, and 9 M, respectively; = 7 in each group). Morphological and mechanical alterations during spontaneous hip osteoarthritis in guinea pigs were investigated. The alterations included the micromechanical properties of articular cartilage (stiffness and creep deformation), microstructure of the subchondral bone (bone mineral density, bone volume fraction, trabecular thickness, trabecular number, and trabecular separation), micromorphology of the articular cartilage, and surface nanostructure (grain size and roughness) of the articular cartilage and subchondral bone. Micromechanical properties of articular cartilage in 1 M showed the lowest stiffness and highest creep deformation with no significant differences in stiffness or creep deformation amongst 3 M, 6 M, and 9 M. Articular cartilage thickness decreased with age. The earliest degeneration of articular cartilage occurred at 6 months of age, characterised by surface unevenness and evident chondrocytes reduction in micromorphology, as well as increased grain size and decreased roughness in nanostructure. No degeneration at micro- or nanostructure of subchondral bone was observed before 9 months. Morphological degeneration of cartilage occurred before degeneration of mechanical properties. Meanwhile, degeneration of cartilage occurred before degeneration of subchondral bone during hip osteoarthritis. The current study provided novel insights into the structural and micromechanical interaction of hip osteoarthritis, which can serve as a theoretical basis for understanding the formation and progression of osteoarthritis.
本研究旨在探讨豚鼠自发性髋关节骨关节炎过程中关节软骨和软骨下骨的形态学及力学变化。对1、3、6和9月龄豚鼠的髋关节进行研究（以下分别表示为1M、3M、6M和9M；每组n = 7）。研究了豚鼠自发性髋关节骨关节炎过程中的形态学和力学改变。这些改变包括关节软骨的微观力学性能（刚度和蠕变变形）、软骨下骨的微观结构（骨矿物质密度、骨体积分数、小梁厚度、小梁数量和小梁间距）、关节软骨的微观形态以及关节软骨和软骨下骨的表面纳米结构（晶粒尺寸和粗糙度）。1M时关节软骨的微观力学性能表现为最低的刚度和最高的蠕变变形，3M、6M和9M之间的刚度或蠕变变形无显著差异。关节软骨厚度随年龄增长而减小。关节软骨最早在6月龄时发生退变，其特征为微观形态上表面不平整和明显的软骨细胞减少，以及纳米结构上晶粒尺寸增大和粗糙度降低。在9月龄之前未观察到软骨下骨微观或纳米结构的退变。软骨的形态学退变先于力学性能退变。同时，在髋关节骨关节炎过程中，软骨退变先于软骨下骨退变。本研究为髋关节骨关节炎的结构和微观力学相互作用提供了新的见解，可为理解骨关节炎的形成和进展提供理论依据。
