Sodium fluorescein-induced changes in leukocyte-endothelial interaction in an animal model

Abstract

Sodium fluorescein (NaF) has been widely used as a contrast dye in clinical practice for the investigation of the chorioretinal microcirculation. Several of its derivatives are also used in fluorescence techniques for microcirculatory research. NaF circulates in blood largely associated with plasma proteins (namely albumin), and, to a shorter extent, with the erythrocyte membrane (Delori et al., 1978). Its presence in circulation has been linked to the occurrence of detrimental effects in blood homeostasis. Jung et al. (1995) reported that NaF angiography decreases microvascular blood flow, as measured by prolongation of retinal circulation time. NaF injection for retinal angiography induces an increase of circulating histamine (Arroyave et al., 1979), suggesting a proinflammatory effect of NaF. Also, an association between in vitro labeling of leukocytes with fluorescein derivatives and modification of their functional properties has been demonstrated (DeClerck et al., 1994), and in other experimental settings fluorescein isothiocyanate is used in vitro as a hapten to elicit nonspecific stimulation of lymphocyte subsets (Hughes et al., 1995). The objective of this preliminary work was to determine the microvascular proinflammatory effects of NaF in an animal experimental model, as measured by leukocyte-endothelial interaction using intravital microscopy.