[Inhibitory Effects of Sphingosine-1-phosphate Receptor-2 on Vascular Permeability in Mice].

OBJECTIVES: To determine the effect of sphingosine-1-phosphate receptor 2 (S1PR2) on vascular permeability in mice.

METHODS: Acute lung injury models of mice were constructed with intra-tracheal administration of lipopolysaccharide (LPS) and compared with the controls with intra-tracheal administration of saline. The effect of S1PR2 on vascular permeability was observed by detecting leakage of Evans blue into lung tissues, pulmonary vascular leakage of fluorescein isothiocyanate (FITC)-dextran, and the wet/dry mass ratio of lungs. The effect of vascular endothelial growth factor (VEGF) on vascular endothelial permeability was detected by Miles analysis.

RESULTS: LPS injections induced significant Evans blue leakage, FITC-dextran pulmonary vascular leakage and pulmonary edema, which appeared to be more serious in S1PR2-deleted mice compared with those in wild-type mice. LPS enhanced Evans blue leakage associated with VEGF in a dose-dependent way in both S1PR2-deleted mice and wild type mice. But the vascular permeability response in subcutaneous tissues induced by VEGF was higher in S1PR2-deleted mice than that in wild-type mice.

CONCLUSIONS: S1PR2 is involved in endothelial cell barrier protections, which inhibits vascular permeability.