Ogawa Mitsugu, Harada Yoshinori, Yamaoka Yoshihisa, Fujita Katsumasa, Yaku Hitoshi, Takamatsu Tetsuro
Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, Kyoto, Japan.
Biochem Biophys Res Commun. 2009 May 1;382(2):370-4. doi: 10.1016/j.bbrc.2009.03.028. Epub 2009 Mar 11.
Label-free imaging is desirable for elucidating morphological and biochemical changes of heart tissue in vivo. Spontaneous Raman microscopy (SRM) provides high chemical contrast without labeling, but presents disadvantage in acquiring images due to low sensitivity and consequent long imaging time. Here, we report a novel technique for label-free imaging of rat heart tissues with high-speed SRM combined with resonance Raman effect of heme proteins. We found that individual cardiomyocytes were identified with resonance Raman signal arising mainly from reduced b- and c-type cytochromes, and that cardiomyocytes and blood vessels were imaged by distinguishing cytochromes from oxy- and deoxy-hemoglobin in intact hearts, while cardiomyocytes and fibrotic tissue were imaged by distinguishing cytochromes from collagen type-I in infarct hearts with principal component analysis. These results suggest the potential of SRM as a label-free high-contrast imaging technique, providing a new approach for studying biochemical changes, based on the molecular composition, in the heart.
无标记成像对于阐明体内心脏组织的形态和生化变化是非常理想的。自发拉曼显微镜（SRM）无需标记即可提供高化学对比度，但由于灵敏度低以及随之而来的长时间成像，在获取图像方面存在劣势。在此，我们报告了一种结合血红蛋白共振拉曼效应的高速SRM对大鼠心脏组织进行无标记成像的新技术。我们发现，单个心肌细胞可通过主要源自还原型b型和c型细胞色素的共振拉曼信号来识别，并且在完整心脏中，通过区分细胞色素与氧合血红蛋白和脱氧血红蛋白来对心肌细胞和血管进行成像，而在梗死心脏中，通过主成分分析区分细胞色素与I型胶原蛋白来对心肌细胞和纤维化组织进行成像。这些结果表明SRM作为一种无标记高对比度成像技术的潜力，为基于心脏分子组成研究生化变化提供了一种新方法。
