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Extravascular Transport of Fluorescently Labeled Albumins in the Rat Mesentery
Author(s) -
HARRIS NORMAN R.,
WHITT STEVAN P.,
ZILBERBERG JENNY,
ALEXANDER J. STEVEN,
RUMBAUT ROLANDO E.
Publication year - 2002
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1038/sj.mn.7800135
Subject(s) - albumin , lymph , chemistry , fluorescein isothiocyanate , microcirculation , vascular permeability , fluorescence , fluorescein , blood proteins , ischemia , pathology , biochemistry , medicine , physics , quantum mechanics
ABSTRACT Objective : Fluorescently labeled albumin is used frequently as a tracer when monitoring microvascular permeability. Several fluorescent dyes are available for labeling protein, including fluorescein isothiocyanate (FITC) and Texas Red (TR). Because differences in leakage of dye‐labeled proteins have been reported, the objective of the present study was to compare the accumulation of these two tracers in interstitium and lymph after the inflammatory event of ischemiareperfusion. Methods : Anesthetized rats were injected intravenously with FITC‐labeled albumin (FITC‐alb) and TR‐labeled albumin (TR‐alb) before 30 minutes of mesenteric ischemia. Because the tracers leaked out of the microcirculation after reperfusion, accumulation in the surrounding buffer‐superfused tissue, and in separate experiments, accumulation in lymph vessels, was defined as the ratio of tissue‐to‐plasma and lymph‐to‐plasma fluorescence. Results : Reperfusion induced a significant increase in tissue‐to‐plasma fluorescence of FITC‐alb; however, no increase was observed for TR‐alb. In contrast, lymph‐to‐plasma fluorescence of TR‐alb tended to be greater than FITC‐alb. Reperfusion‐induced increases in tissue‐to‐plasma fluorescence of TR‐alb occurred only when the superfusate was replaced with mineral oil, in which case tissue‐to‐plasma TR‐alb fluorescence tended to be greater than FITC‐alb. Conclusions : Measurement of fluorescently labeled albumin leakage from mesenteric venules depends on the dye used to label the albumin and requires an assessment of losses from the extravascular measuring region.