University of Manitoba, Department of Chemistry, Winnipeg, Manitoba, R3T 2N2, Canada.
J Biomed Opt. 2011 Jun;16(6):065001. doi: 10.1117/1.3583581.
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.
我们研究了近红外（NIR）荧光染料 Rhodamine 800（Rhod800，λ（excite）= 693nm，λ（emit）> 720nm）作为一种依赖于流动的分子示踪剂，用于近红外光谱和高分辨率心脏成像。Rhod800 与线粒体膜电位（ΔΨ）成正比积聚在分离的线粒体中。然而，在完整的心肌中，Rhod800 结合与ΔΨ无关。用 Krebs-Henseleit 缓冲液以正常（100%）、增加（150%）或减少（50%）的基础冠状动脉流量（CF）/克在 Langendorff 模式下灌注大鼠心脏，持续 30 至 60 分钟。在另一组心脏中，在 Rhod800 输注前闭塞左前降支（LAD）以创建流量不足区域。通过以下方法分析 Rhod800 沉积：1. Rhod800 灌注心脏的吸光度光谱动力学，2. 短轴心脏切片中的 Rhod800 吸光度和荧光成像，以及 3. 在 KCl 停搏心脏中进行 Rhod800 的心动外膜/心外膜荧光成像，空间分辨率约为 200μm。Rhod800 沉积与灌注体积（CF 和灌注时间）成正比，并且在洗脱期间没有 Rhod800 损失。在 LAD 结扎的心脏中，无血流、LAD 依赖性心内膜和心外膜/心外膜区域没有 Rhod800 荧光。我们得出结论，Rhod800 可作为动态心脏成像的沉积流量示踪剂。
