Premium
Quantification of lung microvascular permeability by two‐photon microscopy
Author(s) -
Lindert Jens,
Bhattacharya Jahar
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a554-a
Subject(s) - vascular permeability , chemistry , fluorescence microscope , lung , fluorescence , permeability (electromagnetism) , two photon excitation microscopy , lumen (anatomy) , microscopy , fluorescein , evans blue , pathology , biophysics , medicine , biology , biochemistry , membrane , physics , quantum mechanics
The lung microvascular solute permeability determines lung water content. Here, we applied two‐photon microscopy to determine relative solute permeability ( Sp ). We held isolated blood‐perfused rat lungs at constant pulmonary artery, left atrial and alveolar pressures of 10, 3 and 5 cmH 2 O, respectively. We introduced a venous microcatheder into the lung to infuse a localized area of the vasculature. We infused the cytosolic dye, calcein red AM to load endothelial cells and fluorescently demarcate the vascular lumen. Then, viewing capillaries by two‐photon microscopy, we infused the fluorescent tracer, FITC‐dextran (20 kD, 0.5 mg/ml, 1 ml/h) for 3 min. We determined intravascular and interstitial fluorescence after 10‐min infusions of either buffer (BU) or oleic acid albumin (OA, 40mg/ml). Although intravascular fluorescence increased by 76±4 grey levels (mean±SE, n=3) for both groups, interstitial fluorescence increased 30±6 for BU, but markedly more at 53±5 for OA (P<0.05). We determined FI and FV as slopes of the linear regressions of fluorescence against time for luminal and interstitial fluorescence, respectively. Sp estimated as FI/FV , was 0.5±0.1 for BU, but higher at 0.8±0.1 after OA infusion (P<0.05), indicating that OA increased permeability. We have developed a novel method for quantification of relative solute permeability in lung microvessels. (Support: HL36024, HL78645)