Palombo Francesca, Cremers Stephanie G, Weinberg Peter D, Kazarian Sergei G
Department of Chemical Engineering and Chemical Technology, Imperial College London, London SW7 2AZ, UK.
J R Soc Interface. 2009 Aug 6;6(37):669-80. doi: 10.1098/rsif.2008.0325. Epub 2008 Nov 4.
Diet-induced atherosclerotic lesions in the descending thoracic segment of rabbit aorta were analysed ex vivo by micro-attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectroscopic imaging. The distribution and chemical character of lipid deposits within the arterial wall near intercostal branch ostia were assessed in histological sections from immature and mature rabbits fed cholesterol with or without l-arginine supplements. Previous studies have shown that both these properties change with age in cholesterol-fed rabbits, putatively owing to changes in the synthesis of nitric oxide (NO) from l-arginine. Immature animals developed lesions at the downstream margin of the branch ostium, whereas lipid deposition was observed at the lateral margins in mature animals. Dietary l-arginine supplements had beneficial effects in mature rabbit aorta, with overall disappearance of the plaques; on the other hand, they caused only a slight decrease of the lipid load in lesions at the downstream margin of the ostium in immature rabbits. ATR-FTIR imaging enabled differences in the lipid to protein density ratio of atherosclerotic lesions caused by age and diet to be visualized. Lipid deposits in immature rabbits showed higher relative absorbance values of their characteristic spectral bands compared with those in immature l-arginine-fed rabbits and mature rabbits. The multivariate methods of principal component analysis (PCA) and factor analysis (FA) were employed, and relevant chemical and structural information were obtained. Two distinct protein constituents of the intima-media layer at different locations of the wall were identified using the method of FA. This approach provides a valuable means of investigating the structure and chemistry of complex heterogeneous systems. It has potential for in vivo diagnosis of pathology.
通过显微衰减全反射（ATR）-傅里叶变换红外（FTIR）光谱成像对兔主动脉降段饮食诱导的动脉粥样硬化病变进行离体分析。在喂食含或不含L-精氨酸补充剂胆固醇的未成熟和成熟兔子的组织切片中，评估肋间分支开口附近动脉壁内脂质沉积的分布和化学特征。先前的研究表明，在喂食胆固醇的兔子中，这两种特性都会随年龄变化，推测是由于L-精氨酸合成一氧化氮（NO）的变化所致。未成熟动物在分支开口的下游边缘形成病变，而在成熟动物的外侧边缘观察到脂质沉积。饮食中补充L-精氨酸对成熟兔主动脉有有益作用，斑块总体消失；另一方面，它们仅使未成熟兔子开口下游边缘病变中的脂质负荷略有降低。ATR-FTIR成像能够可视化由年龄和饮食引起的动脉粥样硬化病变中脂质与蛋白质密度比的差异。与喂食L-精氨酸的未成熟兔子和成熟兔子相比，未成熟兔子中的脂质沉积显示出其特征光谱带的相对吸光度值更高。采用主成分分析（PCA）和因子分析（FA）的多变量方法，并获得了相关的化学和结构信息。使用FA方法鉴定了壁不同位置内膜-中膜层的两种不同蛋白质成分。这种方法为研究复杂异质系统的结构和化学提供了一种有价值的手段。它具有体内病理诊断的潜力。
