Applications Of FTIR Spectroscopy And Imaging In The Study Of Gastric Cancer And Traditional Chinese Medicine

FTIR spectroscopy contains abundant molecular structure information and has several advantages such as high sensitivity and easier preparation for samples. When FTIR spectroscopy is combined with a microscope, it can be applied to micro--regional analysis. Thanks to the high brightness of synchrotron source, the small region can be probed by FTIR spectroscopy and imaging with diffraction limited spatial resolution, which will provide richer information than conventional FTIR spectroscopy. Although there have been a lot of reports about the applications of FTIR spectroscopy in biomedical research field, it is still a pressing development areas in biomedical system such as a variety of human tissues and cells, since it is of great importance to obtain structure and spatial distribution changes at molecular level which will be beneficial to early diagnosis and in-depth understanding mechanism of diseases.In this doctoral dissertation, two important systems:gastric cancer and traditional Chinese medicine were chosen as research objects. The following work was carried out:1. Sample preparation methods, test conditions and data processing methods were explored;2. The structures and compositions of gastric cancer tissues (hair, finger nail), saliva and cells were studied by FTIR spectroscopy and imaging, and the differences between malignant samples and normal samples were compared;3. Several representative traditional Chinese medicines (G. lucidum spores, Cortex Eucommice and Dashen) were investigated by FTIR spectroscopy and imaging, and the results showed that FTIR spectroscopy and imaging was efficient and simple for TCM estimation and identification. The following main results were obtained:1. Gastric cancer tissues and cells(1) Gastric cancer tissues (hair, finger nail) and saliva:a. Synchrotron-based FTIR spectroscopy and imaging was used to investigate the hairs from gastric cancer patients and healthy persons. Obvious peak shift of the ymmetric phosphate band was observed in micro-spectra of the medulla region for gastric cancer patients’hair tissues. Chemical images showed the distributions of lipid and amide Ⅱ/vsPO2-changed in the gastric cancer cases.b. FTIR spectroscopy was used to study finger nails from gastric cancer patients and healthy persons. H1045/H1467(glycogen/cholesterol) ratios of gastric s cancer patients’ finger nails were higher than those of healthy persons, and it might be useful for distinguishing the malignant tissues from the normal tissues.c. FTIR spectroscopy was used to study saliva from gastric cancer patients and healthy persons. There were no obvious peak shifts in the spectra. The KSCN content relative to nucleic acids and proteins of gastric caner patients’saliva was lower than that of healthy persons’ saliva.(2) Gastric cancer cell:a. Synchrotron-based FTIR spectroscopy and imaging was used to study human gastric adenocarcinoma cell line SGC7901(moderately differentiated)、BGC823(poorly differentiated) and normal gastric mucosal epithelial cell line GES1. The peak height ratios of1121cm-1/1020cm-1(RNA/DNA, H1121/H1020) of the BGC823and SGC7901cells were significantly higher than those of the GES1cells, and H1121/H1020increased obviously with malignant grade. Furthermore, chemical images revealed that in the most intense absorption region of vasPO2-, the amide Ⅱ/the amide Ⅰ ratio of the SGC7901and BGC823cell was lower than that of the GES1cell, which might be useful for distinguishing malignant cells from normal cells.b. Synchrotron-based FTIR spectroscopy and imaging was used to investigate a single BGC823cell under mitosis. The vsPO2-and vasPO2-peaks’ positions of nucleus were different from those of midbody. ACH3/ACH2, AamideⅠ/AamideⅡ,A(vsPO2-)/AamideⅡ ratios were different between nucleus and midbody. The chemical image of vsPO2-could be used to define the cell’s shape.2. Traditional Chinese medicine G. Lucidum spores, Cortex Eucommice and Danshen(1) Broken cellular wall G. Lucidum spores and G. Lucidum spores were studied by FTIR spectroscopy. It was observed that the structures and contents of lipids, proteins, sugars were different between them. H2956/H2917and H1078/H1640could be used to distinguish them.(2) Synchrotron-based FTIR spectroscopy and imaging was used to investigate cryo-sectioning of Cortex Eucommice and a series of infrared spectra were obtained. Chemical images of cryo-sectioning were also gained and compared in order to know distributions of different chemicals in Cortex Eucommice, and it could provide much more information for us to know the peaks of FTIR further.(3) FTIR spectroscopy was used to study Danshen from different producing areas. The samples’ infrared spectra, secondary derivative infrared spectra and the proteins secondary structures were significantly different. H2958/H2928与A1035/A1629can be used to distinguish Danshen from different producing areas.The above studies show FTIR spectroscopy and imaging plays an important role in biomedical research. The obtained results provide useful information for gastric cancer pathogenesis and diagnosis, and TCM identification. Moreover, they will offer favourable basis for the use of FTIR spectroscopy and imaging in biomedical research.