Department of Physics and Center for Biomedical Research, Oakland University, Rochester, Michigan 48309, USA.
Appl Spectrosc. 2010 Nov;64(11):1199-208. doi: 10.1366/000370210793335124.
Fourier transform infrared imaging (FT-IRI) and principal component regression (PCR) were used to quantitatively determine collagen and proteoglycan concentrations in bovine nasal cartilage (BNC). An infrared spectral library was first established by obtaining eleven infrared spectra from a series of collagen and chondroitin 6-sulfate mixed in different ratios. FT-IR images were obtained from 6-μm-thick sections of BNC specimens at 6.25-μm pixel size. The spectra from the FT-IR images were imported into a PCR program to obtain the relative concentrations of collagen and proteoglycan in BNC, based on the spectral library of pure chemicals. These PCR-determined concentrations agreed with the molecular concentrations determined biochemically using an enzyme digestion assay. Use of the imaging approach revealed that proteoglycan loss in the specimens occurs first at the surface of the tissue block when compared with the middle portion of the tissue block. The quantitative correlation of collagen and proteoglycan revealed that their infrared absorption peak areas at 1338 and 1072-855 cm(-1) can only be used as qualitative indicators of the molecular contents. The use of PCR with FT-IRI offers an accurate tool to spatially determine the distributions of macromolecular concentration in cartilage.
傅里叶变换红外成像（FT-IRI）和主成分回归（PCR）被用于定量测定牛鼻软骨（BNC）中的胶原和蛋白聚糖浓度。首先通过从一系列不同比例混合的胶原和软骨素 6-硫酸盐中获得十一个红外光谱来建立红外光谱库。FT-IRI 图像是从 BNC 标本的 6μm 厚切片以 6.25μm 像素大小获得的。将 FT-IR 图像的光谱导入到 PCR 程序中，根据纯化学物质的光谱库，获得 BNC 中胶原和蛋白聚糖的相对浓度。这些通过 PCR 确定的浓度与使用酶消化测定法从生化角度确定的分子浓度一致。使用成像方法表明，与组织块的中部相比，当与组织块的表面相比时，首先发生组织块中蛋白聚糖的损失。胶原和蛋白聚糖的定量相关性表明，它们在 1338 和 1072-855cm(-1)处的红外吸收峰面积只能用作分子含量的定性指标。FT-IRI 与 PCR 的结合为空间确定软骨中大分子浓度的分布提供了一种准确的工具。
