Fourier transform infrared microscopic imaging (FTIRI) was used to quantitatively examine the anisotropies of proteoglycan (PG) and collagen in articular cartilage. Dried 6 μm thick sections of canine humeral cartilage were imaged at 6.25 μm pixel-size in FTIRI with an infrared analyzer set at 26 different angles between 0° and 180° polarization. Like the amide II and amide III peaks, the 1338 cm(-1) band confirms the anisotropy of collagen fibrils in cartilage. The absorption profile of the sugar band shows an anisotropic flipping at the deeper part in the radial zone, just above the tidemark. Together with the reduction in the PG concentration and subsequent increase in tissue calcification in this region, this anisotropy flipping of sugar might be caused by the orientational change in the collagen-attaching PG from orthogonal to parallel when the fibrils are entering the calcified zone.

中文翻译：

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通过傅里叶变换红外成像研究关节软骨中蛋白多糖的深度依赖性各向异性


傅里叶变换红外显微成像（FTIRI）用于定量检查关节软骨中蛋白多糖（PG）和胶原蛋白的各向异性。使用设置在 0° 和 180° 偏振之间 26 个不同角度的红外分析仪，在 FTIRI 中以 6.25 μm 像素大小对干燥的 6 μm 厚的犬肱骨软骨切片进行成像。与酰胺 II 和酰胺 III 峰一样，1338 cm(-1) 谱带证实了软骨中胶原纤维的各向异性。糖带的吸收剖面显示出在径向区域较深部分（潮位线上方）的各向异性翻转。加上PG浓度的降低和随后该区域组织钙化的增加，糖的这种各向异性翻转可能是由于当原纤维进入钙化区时，胶原蛋白附着的PG从正交到平行的方向变化引起的。