title: Optical imaging of tissue mitochondrial redox state in intact rat lungs in two models of pulmonary oxidative stress.
abstract: Ventilation with enhanced fractions of O(2) (hyperoxia) is a common and necessary treatment for hypoxemia in patients with lung failure, but prolonged exposure to hyperoxia causes lung injury. Ischemia-reperfusion (IR) injury of lung tissue is common in lung transplant or crush injury to the chest. These conditions are associated with apoptosis and decreased survival of lung tissue. The objective of this work is to use cryoimaging to evaluate the effect of exposure to hyperoxia and IR injury on lung tissue mitochondrial redox state in rats. The autofluorescent mitochondrial metabolic coenzymes nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) are electron carriers in ATP generation. These intrinsic fluorophores were imaged for rat lungs using low-temperature fluorescence imaging (cryoimaging). Perfused lungs from four groups of rats were studied: normoxia (control), control perfused with an mitochondrial complex IV inhibitor (potassium cyanide, KCN), rats exposed to hyperoxia (85% O(2)) for seven days, and from rats subjected to lung IR in vivo 24 hours prior to study. Each lung was sectioned sequentially in the transverse direction, and the images were used to reconstruct a three-dimensional (3-D) rendering. In KCN perfused lungs the respiratory chain was more reduced, whereas hyperoxic and IR lung tissue have a more oxidized respiratory chain than control lung tissue, consistent with previously measured mitochondrial dysfunction in both hyperoxic and IR lungs.
authors.affiliation: University of Wisconsin Milwaukee, Biophotonics Lab, Department of Electrical Engineering, Milwaukee, Wisconsin 53211, USA.
authors.forename: Reyhaneh
authors.initials: R
authors.lastname: Sepehr
authors.forename: Kevin
authors.initials: K
authors.lastname: Staniszewski
authors.forename: Sepideh
authors.initials: S
authors.lastname: Maleki
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Jacobs
authors.forename: Said
authors.initials: S
authors.lastname: Audi
authors.forename: Mahsa
authors.initials: M
authors.lastname: Ranji
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002138:Calibration; D003080:Cold Temperature; D005182:Flavin-Adenine Dinucleotide / Q000032:analysis / Q000737:chemistry; D006652:Histological Techniques / Q000379:methods; D018496:Hyperoxia / Q000378:metabolism; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008168:Lung / Q000737:chemistry / Q000378:metabolism*; D055370:Lung Injury / Q000378:metabolism*; D008297:Male; D008856:Microscopy, Fluorescence / Q000379:methods*; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D009243:NAD / Q000032:analysis / Q000737:chemistry; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000378:metabolism
chemical_list: D009243:NAD; D005182:Flavin-Adenine Dinucleotide