Substance P prevents vascular leakage in the mouse retina. Groups of C57BL/6J mice received intravitreal injections of SP (20 nmol), VEGF (100 ng), SP in combination with VEGF or vehicle control (n = 6 per group). (A) Representative images 48 h following treatment demonstrate differences in the vasculature (leakage of Evans blue dye, which appears as red). Scale bar = 50 μm. (B) The fluorescent intensity of Evans blue was quantified by Image J. (C) Representative confocal images of retinal vessels immunostained with ZO-1. Scale bar = 20 μm. Data represents means ± SD of relative values vs control from 3 independent experiments. *P < 0.05; **P < 0.01; ***P < 0.001, statistical analysis was performed with one-way ANOVA with Dunn's test for multiple comparisons. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)