title: Time-resolved in situ measurement of mitochondrial malfunction by energy transfer spectroscopy.
abstract: To establish optical in situ detection of mitochondrial malfunction, nonradiative energy transfer from the coenzyme NADH to the mitochondrial marker rhodamine 123 (R123) was examined. Dual excitation of R123 via energy transfer from excited NADH molecules as well as by direct absorption of light results in two fluorescence signals whose ratio is a measure of mitochondrial NADH. A screening system was developed in which these signals are detected simultaneously using a time-gated (nanosecond) technique for energy transfer measurements and a frequency selective technique for direct excitation and fluorescence monitoring of R123. Optical and electronic components of the apparatus are described, and results obtained from cultivated endothelial cells are reported. The ratio of fluorescence intensities excited in the near ultraviolet and blue-green spectral ranges increased by a factor 1.5 or 1.35 after inhibition of the mitochondrial respiratory chain by rotenone at cytotoxic or noncytotoxic concentrations, respectively. Concomitantly the amount of mitochondrial NADH increased. Excellent linearity between the number of cells incubated with R123 and fluorescence intensity was found in suspension.
authors.affiliation: Institut für Lasertechnologien in der Medizin und Messtechnik an der Universität Ulm, Germany. herbert.schneckenburger@fh-aalen.de
authors.forename: H
authors.initials: H
authors.lastname: Schneckenburger
authors.forename: M H
authors.initials: MH
authors.lastname: Gschwend
authors.forename: R
authors.initials: R
authors.lastname: Sailer
authors.forename: W S
authors.initials: WS
authors.lastname: Strauss
authors.forename: M
authors.initials: M
authors.lastname: Lyttek
authors.forename: K
authors.initials: K
authors.lastname: Stock
authors.forename: P
authors.initials: P
authors.lastname: Zipfl
mesh_terms: D000818:Animals; D015415:Biomarkers; D002417:Cattle; D004730:Endothelium, Vascular / Q000378:metabolism / Q000648:ultrastructure; D004735:Energy Transfer / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D009243:NAD / Q000378:metabolism*; D020112:Rhodamine 123 / Q000378:metabolism*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D015415:Biomarkers; D009243:NAD; D020112:Rhodamine 123