title: Label-free detection of myocardial ischaemia in the perfused rat heart by spontaneous Raman spectroscopy.
abstract: Raman spectroscopy, which identifies intrinsic molecular constituents, has a potential for determining myocardial viability under label-free conditions. However, its suitability for evaluating myocardial ischaemia is undetermined. Focusing on cytochromes, i.e., representative molecules reflecting mitochondrial activity, we tested whether Raman spectroscopy is applicable for evaluating myocardial ischaemia especially during early ischaemic phase. We obtained spontaneous Raman spectra of the subepicardial myocardium in the Langendorff-perfused rat heart upon 532-nm excitation before and during the "stopped-flow," global ischaemia. Semi-quantitative values of the peak intensities at 750 and 1127 cm-1, which reflect reduced cytochromes c and b, increased immediately and progressively after induction of the stopped flow, indicating progressive reduction of the mitochondrial respiration. Such spectral changes emerged before the loss of 1) mitochondrial membrane potentials measured by the fluorescence intensity of tetramethyl rhodamine ethyl ester or 2) staining of the triphenyl tetrazolium chloride dye in the myocardium. The progressive increases in the Raman peaks by stopped flow were significantly retarded by ischaemic preconditioning. Sequential measurements of the peak intensities at 750 and 1127 cm-1enabled early detection of the myocardial ischaemia based on the mitochondrial functions. These data suggest that Raman spectroscopy offers the potential to evaluate acute ischaemic heart under label-free conditions.
authors.affiliation: Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.|Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.
authors.forename: Suguru
authors.initials: S
authors.lastname: Ohira
authors.affiliation: Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Harada
authors.affiliation: Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.|Tokushima University, Graduate School of Science and Technology, 2-1, Minami-Josanjima, Tokushima 770-8506, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Minamikawa
authors.affiliation: Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Kumamoto
authors.affiliation: Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.
authors.forename: Satoaki
authors.initials: S
authors.lastname: Matoba
authors.affiliation: Department of Cardiovascular Surgery, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yaku
authors.affiliation: Department of Medical Photonics, Kyoto Prefectural University of Medicine, 465 Kajii-cho Kawaramachi-Hirokoji, Kamigyo-Ku, Kyoto 602-8566, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Takamatsu
mesh_terms: D000818:Animals; D019157:Ischemic Preconditioning, Myocardial; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000378:metabolism; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000378:metabolism* / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D010101:Oxygen Consumption; D051381:Rats; D013059:Spectrum Analysis, Raman / Q000379:methods; D059008:Time-Lapse Imaging