title: Rhodamine 800 as a near-infrared fluorescent deposition flow tracer in rodent hearts.
abstract: We investigated the use of a near-infrared (NIR) fluorescent dye, Rhodamine 800 (Rhod800, λ(exc) = 693 nm, λ(em) > 720 nm) as a flow-dependent molecular tracer for NIR spectroscopy and high-resolution cardiac imaging. Rhod800 accumulates in isolated mitochondria in proportion to the mitochondrial membrane potential (ΔΨ). However, in the intact myocardium, Rhod800 binding is ΔΨ-independent. Rat hearts were perfused in a Langendorff mode with Krebs-Henseleit buffer containing 45-nM Rhod800 at normal (100%), increased (150%), or reduced (50%) baseline coronary flow (CF) per gram, for 30 to 60 min. In a different group of hearts, the left anterior descending artery (LAD) was occluded prior to Rhod800 infusion to create a flow deficit area. Rhod800 deposition was analyzed by: 1. absorbance spectroscopy kinetics in the Rhod800-perfused hearts, 2. Rhod800 absorbance and fluorescence imaging in the short-axis heart slices, and 3. dynamic epicardial/subepicardial fluorescence imaging of Rhod800 in KCl-arrested hearts, with a spatial resolution of ∼ 200 μm. Rhod800 deposition was proportional to the perfusate volume (CF and perfusion time) and there was no Rhod800 loss during the washout period. In the LAD-ligated hearts, Rhod800 fluorescence was missing from the no-flow, LAD-dependent endocardial and epicardial/subepicardial area. We concluded that Rhod800 can be used as a deposition flow tracer for dynamic cardiac imaging.
authors: University of Manitoba, Department of Chemistry, Winnipeg, Manitoba, R3T 2N2, Canada.
authors: Garret
authors: G
authors: Munch
authors: Scott
authors: S
authors: McKay
authors: Eugene
authors: E
authors: Gussakovsky
authors: Bozena
authors: B
authors: Kuzio
authors: Valery V
authors: VV
authors: Kupriyanov
authors: Olga
authors: O
authors: Jilkina
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry* / Q000493:pharmacokinetics; D005260:Female; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D016018:Least-Squares Analysis; D008297:Male; D008929:Mitochondria, Heart / Q000737:chemistry / Q000378:metabolism; D017202:Myocardial Ischemia / Q000378:metabolism / Q000473:pathology; D009206:Myocardium / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY; D012235:Rhodamines / Q000737:chemistry* / Q000493:pharmacokinetics; D013050:Spectrometry, Fluorescence / Q000379:methods*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D003287:Contrast Media; D012235:Rhodamines; C105720:rhodamine 800