Novel Flurometric Tool to Assess Mitochondrial Redox State of Isolated Perfused Rat Lungs after Exposure to Hyperoxia
Recently we demonstrated the utility of optical fluorometry to detect a change in the redox status of mitochondrial autofluorescent coenzymes NADH (Nicotinamide Adenine Dinucleotide) and FAD (oxidized form of Flavin Adenine Dinucleotide (FADH2,)) as a measure of mitochondrial function in isolated perfused rat lungs (IPL). The objective of this study was to utilize optical fluorometry to evaluate the effect of rat exposure to hyperoxia (>95% O2 for 48 hours) on lung tissue mitochondrial redox status of NADH and FAD in a nondestructive manner in IPL. Surface NADH and FAD signals were measured before and after lung perfusion with perfusate containing rotenone (ROT, complex I inhibitor), potassium cyanide (KCN, complex IV inhibitor), and/or pentachlorophenol (PCP, uncoupler). ROT- or KCN-induced increase in NADH signal is considered a measure of complex I activity, and KCN-induced decrease in FAD signal is considered a measure of complex II activity. The results show that hyperoxia decreased complex I and II activities by 63% and 55%, respectively, as compared to lungs of rats exposed to room air (normoxic rats). Mitochondrial complex I and II activities in lung homogenates were also lower (77% and 63%, respectively) for hyperoxic than for normoxic lungs. These results suggest that the mitochondrial matrix is more reduced in hyperoxic lungs than in normoxic lungs, and demonstrate the ability of optical fluorometry to detect a change in mitochondrial redox state of hyperoxic lungs prior to histological changes characteristic of hyperoxia.
View full article
See complete bios of the authors in the full version of this article.
Ms. Sepehr has B.S. and M.S. in biomedical engineering from Amirkabir University of Technology (Tehran, Iran), and currently is a PhD candidate in the electrical engineering department at the University of Wisconsin-Milwaukee.
Dr. Audi is an Associate Professor of Biomedical Engineering at Marquette University. His research interests have been primary in mathematical modeling of physiologic systems, including in the areas of pulmonary mass transfer, pulmonary hemodynamics, and functional imaging.
Mr. Staniszewski has a B.S. in Electrical Engineering from the University of Wisconsin-Milwaukee. He then continued to obtain his M.S. in Electrical Engineering from the same university with a concentration in biophotonics.
Mr. Haworth is a Research Scientist in Pulmonary and Critical Care Medicine at the Medical College of Wisconsin and a Research Engineer at the Zablocki VA Medical Center. His interests focus on using a range of medical imaging modes as tools for understanding the overall structural, functional and metabolic relationships of the pulmonary vascular system under various compromised diseased states.
Ms. Jacobs is a Professor of Pulmonary and Critical Care Medicine at the Medical College of Wisconsin and the Associate Chief of Staff at the Zablocki VA Medical Center. Her interest is in mechanisms underlying acute lung injury as well as novel diagnostics to better identify pulmonary injury.
Ms. Ranji is an Assistant Professor in Electrical Engineering department at University of Wisconsin-Milwaukee. She is the director of Biophotonics Laboratory with research focus on optical imaging, and image processing of tissue metabolism.
This article appeared in the 2013 issue of IEEE Journal of Translational Engineering in Health and Medicine.
View all articles on IEEE Xplore