University of Western Australia, School of Mechanical and Chemical Engineering, Perth, Western Australia 6009, Australia.
J Biomed Opt. 2013 Oct;18(10):105003. doi: 10.1117/1.JBO.18.10.105003.
The depth distributions of refractive index (RI) in normal and early degenerated articular cartilage (AC) were measured and correlated to the pathological statuses. Utilizing a confocal microscope, the depth distribution of RI was determined with an interval of 50 μm from the articular surface and approximated as a smooth curve. The fluctuation of RI was quantified with a specially defined coefficient and the proteoglycan (PG) loss was quantified with histological images. The overall RI of the AC collected from the femoral condyles of mature sheep was 1.4444. Significant differences existed in the refractive indices of different cartilage samples or even in the different depths of the same sample. The RI of normal cartilage distributed as a regular ramp or arch curve with depth and peaked in the middle-deep zone. The cartilage samples detected with high PG losses were coupled with severe fluctuations of RI. The fluctuating level was increased with pathological progress. The coefficient of RI fluctuation can distinguish the normal cartilage from the initially degenerated one, which potentially provides an indicator to detect the pathological development of AC.
正常和早期退变关节软骨（AC）的折射率（RI）深度分布进行了测量，并与病理状态相关联。利用共聚焦显微镜，从关节表面每隔 50μm 测定 RI 的深度分布，并近似为平滑曲线。用专门定义的系数量化 RI 的波动，并用组织学图像量化蛋白聚糖（PG）的损失。从成熟绵羊股骨髁采集的 AC 的整体 RI 为 1.4444。不同软骨样本或同一样本的不同深度的 RI 存在显著差异。正常软骨的 RI 分布呈深度的规则斜坡或拱形曲线，在中深层达到峰值。PG 损失较高的软骨样本与 RI 的剧烈波动相关。波动水平随着病理进展而增加。RI 波动系数可区分正常软骨和早期退变软骨，这可能为检测 AC 的病理发展提供一个指标。
