Joukar Amin, Karnik Sonali, Noori-Dokht Hessam, Younesi Sogol, Trippel Stephen B, Wagner Diane R
School of Mechanical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
Department of Orthopaedic Surgery, Indiana University School of Medicine, 723 W. Michigan Street, SL 260, Indianapolis, IN, 46202, USA.
Ann Biomed Eng. 2025 Apr;53(4):956-965. doi: 10.1007/s10439-025-03680-8. Epub 2025 Jan 25.
To evaluate the mechanical wear of cartilage with different types of degradation.
Bovine osteochondral explants were treated with interleukin-1β (IL-1β) to mimic inflammatory conditions, with chondroitinase ABC (ChABC) to specifically remove glycosaminoglycans (GAGs), or with collagenase to degrade the collagen network during 5 days of culture. Viscoelastic properties of cartilage were characterized via indentation. Biochemical assays were performed to quantify the cartilage matrix loss to the media during culture and from an accelerated, ex vivo wear test. The coefficient of friction during the wear test was measured. Distribution of GAGs in the tissue was assessed histologically.
All three degradative treatments decreased the cartilage modulus values and depleted GAGs in histological sections. However, wear was not uniform among the different treatments. Collagen loss from the tissue due to mechanical wear was only higher with IL-1β and collagenase treatment, while collagen loss due to wear with ChABC treatment was similar to untreated controls. In addition, less GAG was released due to mechanical wear in all degraded groups than the controls, likely because GAGs had already been depleted from these tissues during culture. As no significant differences in the coefficient of friction were observed between groups, changes in wear were attributed to altered tissue composition and structure rather than to changes in frictional forces.
Results suggest that cartilage with a degraded collagen network is more susceptible to mechanical wear, but that cartilage wear may be relatively unaffected by the loss of GAGs. Furthermore, exacerbated mechanical wear could be an additional mechanism by which inflammatory cytokines induce cartilage breakdown.
评估不同类型降解情况下软骨的机械磨损情况。
牛骨软骨外植体分别用白细胞介素-1β（IL-1β）处理以模拟炎症状态，用软骨素酶ABC（ChABC）特异性去除糖胺聚糖（GAGs），或用胶原酶在培养5天期间降解胶原网络。通过压痕表征软骨的粘弹性特性。进行生化分析以量化培养期间及加速体外磨损试验中软骨基质向培养基中的损失。测量磨损试验期间的摩擦系数。通过组织学评估GAGs在组织中的分布。
所有三种降解处理均降低了软骨模量值，并使组织学切片中的GAGs减少。然而，不同处理之间的磨损并不均匀。仅在IL-1β和胶原酶处理后，由于机械磨损导致的组织胶原损失更高，而ChABC处理导致的磨损引起的胶原损失与未处理的对照相似。此外，与对照组相比，所有降解组中由于机械磨损释放的GAG更少，这可能是因为在培养期间这些组织中的GAG已经被耗尽。由于各组之间未观察到摩擦系数的显著差异，磨损的变化归因于组织组成和结构的改变而非摩擦力的变化。
结果表明，胶原网络降解的软骨更容易受到机械磨损，但软骨磨损可能相对不受GAGs损失的影响。此外，加剧的机械磨损可能是炎性细胞因子诱导软骨破坏的另一种机制。
