Fig. 4

Treg expansion reduces diabetes-associated vascular damage and alteration of thickness. A, Fundus fluorescein (fluorescein sodium) image of db/+, db/db and db/db receiving either IL-2/anti-IL-2 or its isotype. In yellow, magnified image of the area. The arrowhead indicates vascular tortuosity in db/db animals and and db/db treated with IL-2/isotype. B-D, Representative images of retinal sections (B) showing retinal barrier leakage, visualized using isolectin B4 (green) and albumin (red) staining. The quantification includes the number of leakage spots per mm of retina (C) and the average size of the leakage spots (in µm²) (D). The leakage spots/areas were determined by counting the number of albumin⁺ and isolectin B4⁻ spots and measuring the area of albumin⁺ regions in retinal sections. White arrowheads indicate larger or more extensive areas of leakage, while yellow arrowheads mark smaller areas of leakage. Scale bar 25 μm. n = 4–8 (C) and n = 3–6 (D). E, Quantification of VEGF concentration in the retina, normalized to the total protein in the retina. n = 4–5. Data presented as mean ± s.e.m. *P < 0.05; ** P < 0.01; 1-way ANOVA followed by Tukey’s multiple comparisons test