University of Eastern Finland, Department of Applied Physics, FI-70211 Kuopio, FinlandbKuopio University Hospital, Department of Clinical Neurophysiology, FI-70029 Kuopio, Finland.
J Biomed Opt. 2013 Sep;18(9):097006. doi: 10.1117/1.JBO.18.9.097006.
Fourier transform infrared (FTIR) microspectroscopy has been used to estimate the spatial proteoglycan (PG) and collagen contents in articular cartilage (AC). However, it is not clear whether the results of FTIR analyses are consistent between different species. Our aim was to clarify how three different FTIR PG parameters in use, i.e., the integrated absorbance in the carbohydrate region, the carbohydrate/amide I ratio, and the second derivative peak at 1062 cm-1, can indicate the densitometrically assessed (reference method) spatial PG content in a sample set consisting of osteoarthritic human and bovine AC samples. The results show that all the parameters can accurately reflect the PG content, when the species are analyzed separately. When all samples are pooled, the correlation with the reference method is high (r=0.760, n=104) for the second derivative peak at 1062 cm-1 and is significantly lower (p<0.05) for the carbohydrate region (r=0.587, n=104) and for the carbohydrate/amide I ratio (r=0.579, n=104). Therefore, the analysis of the carbohydrate region may provide inconsistent results, if the cartilage samples from different species are in use. Based on the present study, second derivative analysis yields more consistent results for human and bovine cartilages.
傅里叶变换红外（FTIR）微光谱已被用于估计关节软骨（AC）中空间糖蛋白（PG）和胶原蛋白的含量。然而，FTIR 分析的结果在不同物种之间是否一致尚不清楚。我们的目的是阐明三种不同的 FTIR PG 参数，即碳水化合物区域的积分吸光度、碳水化合物/酰胺 I 比以及 1062cm-1 处的二阶导数峰，如何能够指示由骨关节炎患者和牛的 AC 样本组成的样本集中的空间 PG 含量的密度测定法（参考方法）。结果表明，当分别分析物种时，所有参数都可以准确反映 PG 含量。当所有样本混合时，1062cm-1 处的二阶导数峰与参考方法的相关性很高（r=0.760，n=104），而碳水化合物区域（r=0.587，n=104）和碳水化合物/酰胺 I 比（r=0.579，n=104）的相关性则明显较低（p<0.05）。因此，如果使用来自不同物种的软骨样本，分析碳水化合物区域可能会得出不一致的结果。基于本研究，二阶导数分析为人类和牛软骨提供了更一致的结果。
