Lodz University of Technology, Faculty of Chemistry, Institute of Applied Radiation Chemistry, Laboratory of Laser Molecular Spectroscopy, Wroblewskiego 15, 93-590 Lodz, Poland.
Lodz University of Technology, Faculty of Chemistry, Institute of Applied Radiation Chemistry, Laboratory of Laser Molecular Spectroscopy, Wroblewskiego 15, 93-590 Lodz, Poland.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Jan 5;188:8-19. doi: 10.1016/j.saa.2017.06.037. Epub 2017 Jun 30.
Raman spectroscopy and imaging combined with AFM topography and mechanical indentation by AFM have been shown to be an effective tool for analysis and discrimination of human brain tumors from normal structures. Raman methods have potential to be applied in clinical practice as they allow for identification of tumor margins during surgery. In this study, we investigate medulloblastoma (grade IV WHO) (n=5) and the tissue from the negative margins used as normal controls. We compare a high grade medulloblastoma (IV grade), and non-tumor samples from human central nervous system (CNS) tissue. Based on the properties of the Raman vibrational spectra and Raman images we provide a real-time feedback that is label-free method to monitor tumor metabolism that reveals reprogramming of biosynthesis of lipids, and proteins. We have found that the high-grade tumors of central nervous system (medulloblastoma) exhibit enhanced level of β-sheet conformation and down-regulated level of α-helix conformation when comparing against normal tissue. We have shown that the ratio of Raman intensities I2930/I2845 at 2930 and 2845cm is a good source of information on the ratio of lipid and protein contents. We have found that the ratio reflects the lipid and protein contents of tumorous brain tissue compared to the non-tumor tissue. Almost all brain tumors have the Raman intensity ratios significantly higher (1.99±0.026) than that found in non-tumor brain tissue, which is 1.456±0.02, and indicates that the relative amount of lipids compared to proteins is significantly higher in the normal brain tissue. Mechanical indentation using AFM on sliced human brain tissues (medulloblastoma, grade IV) revealed that the mechanical properties of this tissue are strongly heterogeneous, between 1.8 and 75.7kPa, and the mean of 27.16kPa. The sensitivity and specificity obtained directly from PLSDA and cross validation gives a sensitivity and specificity of 98.5% and 96% and 96.3% and 92% for cross-validation, respectively. The high sensitivity and specificity demonstrates usefulness for a proper decision for a Raman diagnostic test on biochemical alterations monitored by Raman spectroscopy related to brain cancer development.
拉曼光谱和成像与原子力显微镜形貌和机械压痕相结合，已被证明是分析和区分人脑肿瘤与正常结构的有效工具。拉曼方法有可能应用于临床实践，因为它们允许在手术过程中识别肿瘤边界。在这项研究中，我们研究了髓母细胞瘤（IV 级世界卫生组织）（n=5）和用作正常对照的阴性边界组织。我们比较了高级别髓母细胞瘤（IV 级）和来自人类中枢神经系统（CNS）组织的非肿瘤样本。基于拉曼振动光谱和拉曼图像的特性，我们提供了实时反馈，这是一种无标记的方法，可以监测肿瘤代谢，揭示脂质和蛋白质生物合成的重编程。我们发现，与正常组织相比，中枢神经系统（髓母细胞瘤）的高级别肿瘤表现出增强的β-折叠构象水平和下调的α-螺旋构象水平。我们已经表明，在 2930 和 2845cm 处的 Raman 强度比 I2930/I2845 是脂质和蛋白质含量比的良好信息源。我们发现该比值反映了肿瘤脑组织与非肿瘤组织相比的脂质和蛋白质含量。几乎所有的脑肿瘤的 Raman 强度比值都显著高于（1.99±0.026）在非肿瘤脑组织中发现的比值，即 1.456±0.02，这表明在正常脑组织中，与蛋白质相比，脂质的相对含量显著更高。使用 AFM 对切片人脑组织（髓母细胞瘤，IV 级）进行机械压痕，发现该组织的力学性质具有很强的异质性，在 1.8 和 75.7kPa 之间，平均值为 27.16kPa。直接从 PLSDA 和交叉验证获得的灵敏度和特异性分别为 98.5%和 96%，交叉验证的特异性分别为 96.3%和 92%。高灵敏度和特异性表明，拉曼光谱监测的与脑癌发展相关的生化变化的拉曼诊断测试具有适当决策的有用性。
