title: Surface fluorescence studies of tissue mitochondrial redox state in isolated perfused rat lungs.
abstract: We designed a fiber-optic-based optoelectronic fluorometer to measure emitted fluorescence from the auto-fluorescent electron carriers NADH and FAD of the mitochondrial electron transport chain (ETC). The ratio of NADH to FAD is called the redox ratio (RR = NADH/FAD) and is an indicator of the oxidoreductive state of tissue. We evaluated the fluorometer by measuring the fluorescence intensities of NADH and FAD at the surface of isolated, perfused rat lungs. Alterations of lung mitochondrial metabolic state were achieved by the addition of rotenone (complex I inhibitor), potassium cyanide (KCN, complex IV inhibitor) and/or pentachlorophenol (PCP, uncoupler) into the perfusate recirculating through the lung. Rotenone- or KCN-containing perfusate increased RR by 21 and 30%, respectively. In contrast, PCP-containing perfusate decreased RR by 27%. These changes are consistent with the established effects of rotenone, KCN, and PCP on the redox status of the ETC. Addition of blood to perfusate quenched NADH and FAD signal, but had no effect on RR. This study demonstrates the capacity of fluorometry to detect a change in mitochondrial redox state in isolated perfused lungs, and suggests the potential of fluorometry for use in in vivo experiments to extract a sensitive measure of lung tissue health in real-time.
authors.affiliation: Biophotonics Lab, Department of Electrical Engineering, University of Wisconsin Milwaukee, 3200 N Cramer St., Milwaukee, WI 53211, USA. kevinss2@uwm.edu
authors.forename: Kevin
authors.initials: K
authors.lastname: Staniszewski
authors.forename: Said H
authors.initials: SH
authors.lastname: Audi
authors.forename: Reyhaneh
authors.initials: R
authors.lastname: Sepehr
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Jacobs
authors.forename: Mahsa
authors.initials: M
authors.lastname: Ranji
mesh_terms: D000818:Animals; D001698:Biomedical Engineering; D004867:Equipment Design; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D005470:Fluorometry / Q000295:instrumentation* / Q000379:methods; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism*; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D055100:Optical Fibers; D010084:Oxidation-Reduction; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D009243:NAD; D005182:Flavin-Adenine Dinucleotide