University of Oulu, Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, Oulu, FinlandbUniversity of Eastern Finland, Department of Applied Physics, Kuopio, Finland.
South Karelia Central Hospital, Department of Radiology, Lappeenranta, Finland.
J Biomed Opt. 2017 Mar 1;22(3):35007. doi: 10.1117/1.JBO.22.3.035007.
Collagen forms an organized network in articular cartilage to give tensile stiffness to the tissue. Due to its long half-life, collagen is susceptible to cross-links caused by advanced glycation end-products. The current standard method for determination of cross-link concentrations in tissues is the destructive high-performance liquid chromatography (HPLC). The aim of this study was to analyze the cross-link concentrations nondestructively from standard unstained histological articular cartilage sections by using Fourier transform infrared (FTIR) microspectroscopy. Half of the bovine articular cartilage samples ( n = 27 ) were treated with threose to increase the collagen cross-linking while the other half ( n = 27 ) served as a control group. Partial least squares (PLS) regression with variable selection algorithms was used to predict the cross-link concentrations from the measured average FTIR spectra of the samples, and HPLC was used as the reference method for cross-link concentrations. The correlation coefficients between the PLS regression models and the biochemical reference values were r = 0.84 ( p < 0.001 ), r = 0.87 ( p < 0.001 ) and r = 0.92 ( p < 0.001 ) for hydroxylysyl pyridinoline (HP), lysyl pyridinoline (LP), and pentosidine (Pent) cross-links, respectively. The study demonstrated that FTIR microspectroscopy is a feasible method for investigating cross-link concentrations in articular cartilage.
胶原蛋白在关节软骨中形成有组织的网络，为组织提供拉伸刚度。由于其半衰期长，胶原蛋白容易受到糖基化终产物引起的交联影响。目前测定组织中交联浓度的标准方法是破坏性高效液相色谱 (HPLC)。本研究旨在通过傅里叶变换红外 (FTIR) 微光谱分析，从标准未染色的关节软骨组织切片中无损地分析交联浓度。一半的牛关节软骨样本（n = 27）用苏糖处理以增加胶原蛋白交联，而另一半（n = 27）作为对照组。使用偏最小二乘（PLS）回归与变量选择算法，根据样本的平均 FTIR 光谱预测交联浓度，HPLC 作为交联浓度的参考方法。PLS 回归模型与生化参考值之间的相关系数分别为 r = 0.84（p < 0.001）、r = 0.87（p < 0.001）和 r = 0.92（p < 0.001），分别用于羟赖氨酸吡啶啉 (HP)、赖氨酰吡啶啉 (LP) 和戊糖胺 (Pent) 交联。该研究表明，FTIR 微光谱是一种可行的方法，可用于研究关节软骨中的交联浓度。
