FTIR-HATR诊断β-地中海贫血及其机理研究

FTIR-HATR to Identify β-Thalassemia and Its Mechanism Study

为建立简单快速的地中海贫血(简称地贫)诊断方法,探讨了傅里叶红外光谱结合水平衰减全反射(FTIR-HATR)技术用于β-地贫患者的检测及其分子机制。检测了68份正常与37份β-重型地贫患者样品,并在群体水平上分析了两者光谱差异变化规律。结果显示:(1)由于血红蛋白量的减少,β-地贫组的光谱强度显著低于正常组;(2)在1750～1500cm-1区间,表征蛋白二级结构的1652,1638和1628cm-1在β-地贫中有明显降低,而在1682cm-1处略微增强;(3)在1350～1500cm-1区间,表征磷脂CH3/CH2的1440,1453,1479cm-1及CO—O—C的1172和1161cm-1吸收峰在β-地贫中显著减少;而在1000～1200cm-1区间,表征碳水化合物C—O的1150cm-1,2,3-二磷酸甘油酸(DPG)或ATP中OPO的1081和1053cm-1吸收峰显著升高。统计表明DPG/脂类比在β-重型地贫组中显著高于正常组,并可作为诊断指标,将两者完全区分,避免了复杂数据处理过程,为地贫的光谱诊断提供了坚实的实验基础与理论依据。

Fourier transform infrared spectroscopy （FTIR）associated with horizontal attenuated total reflectance （HATR）was firstly used to diagnose ffthalassemia patients. With excellent linearity （r=0. 997） and reproducibility （RSD〈4%）, FTIR-HATR shows an order-of-magnitude increase in IR absorption bands over the single-path transmission FTIR. Based on above, spectra from 37 patients＇ and 68 health samples indicated several observable differences in IR vibrational spectra of the Hb lysates between the β-thalassemia major patients and control： （1）Because of decreasing hemoglobin, the peak intensities are obviously lower in β-thalassemia group that is consistent with index from routine hemoglobin diagnosis. （2）In 1750-1 500 cm^-1 region, slight decrease at 1 652 cm^- 1 （α-helix）, 1 638 and 1 628 cm^-1 bands but mild increase at 1 682 cm^- 1 all demonstrate structure changes by both Fourier self-deconvolution and second derivative spectra. （3）More importantly, difference spectra substantially demonstrate decreased intensities at 1 440, 1 453, 1 479 cm^- 1 bands arising from CH2/CH3 deformation vibration of phospholipids but increased intensities at 1 150 cm^ -1 band originating from C-O stretching vibration of carbohydrate and at 1 081 and 1 053 cm^-1 bands that are attributed to 2,3-diphosphoglycerate （DPG）in ffthalassemia major group. Statistical analysis demonstrates significant difference of DPG/phospholipids ratio between two groups. All the samples can be 100% correctly classified into groups on the basis of this ratio. These finding could help understand possible mechanism for diagnosing thalassemia. It makes large-scale screening of thalassemia by FTIR a possibility.