Wu Yicong, Qu Jianan Y
Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology, Clear Water Bay Road, Kowloon, Hong Kong, China.
J Biomed Opt. 2006 Sep-Oct;11(5):054023. doi: 10.1117/1.2362741.
Autofluorescence of rabbit and human epithelial tissues were studied by using a depth-resolved fluorescence spectroscopy system with multiple excitations. Keratinization was found to be common in the squamous epithelium. Strong keratin fluorescence with excitation and emission characteristics similar to collagen were observed in the topmost layer of the keratinized squamous epithelium. The keratin signal created interference in the assessment of the endogenous fluorescence signals (NADH/FAD fluorescence in epithelium and collagen fluorescence in stroma) associated with the development of epithelial precancer. Furthermore, the keratinized epithelial layer attenuated the excitation light and reduced the fluorescence signals from underlying tissue layers. The autofluorescence of columnar epithelium was found to be dominated by NADH and FAD signals, identical to the autofluorescence measured from nonkeratinized squamous epithelium. The study also demonstrated that a fluorescence signal excited at 355 nm produced sufficient contrast to resolve the layered structure of epithelial tissue, while the signal excited at 405 nm provided the information for a good estimation of epithelial redox ratios that are directly related to tissue metabolism. Overall, the depth-resolved measurements are crucial to isolate the fluorescence signals from different sublayers of the epithelial tissue and provide more accurate information for the tissue diagnosis.
利用具有多种激发光的深度分辨荧光光谱系统研究了兔和人上皮组织的自发荧光。发现角化在鳞状上皮中很常见。在角化鳞状上皮的最上层观察到具有与胶原蛋白相似的激发和发射特征的强角蛋白荧光。角蛋白信号在评估与上皮癌前病变发展相关的内源性荧光信号（上皮中的NADH/FAD荧光和基质中的胶原蛋白荧光）时产生干扰。此外，角化上皮层衰减激发光并减少来自下层组织层的荧光信号。发现柱状上皮的自发荧光主要由NADH和FAD信号主导，这与从非角化鳞状上皮测量的自发荧光相同。该研究还表明，在355nm激发的荧光信号产生了足够的对比度以分辨上皮组织的分层结构，而在405nm激发的信号提供了用于良好估计与组织代谢直接相关的上皮氧化还原比的信息。总体而言，深度分辨测量对于分离上皮组织不同亚层的荧光信号并为组织诊断提供更准确的信息至关重要。
