Fig. 5

M2-exo attenuates retinal vascular leakage and reduces the number of acellular capillaries. A Three-dimensional view of a frozen retinal section of mice with STZ-induced DR showing exosome uptake in vivo. Scale bar = 100 μm. B, C E/P ratio, number of acellular strands, and morphological changes in vessels among the four groups assessed using PAS staining of retinal tissue (*p < 0.05, **p < 0.01). White arrows indicate acellular strands. n = 5. Scale bar = 50 μm. E/P endothelial cell-to-pericyte. D, E Microvascular permeability of whole retinal branches evaluated by Evans blue fluorescence staining. Dye leakage was observed outwards from the retinal vessels in the STZ-induced DR mouse model, whereas almost no Evans blue leakage was observed in the M2-exo-treated group. *p < 0.05, **p < 0.01***p < 0.001; n = 5. Scale bar = 200 μm. F Quantification of Evans blue content in the retina. ***p < 0.001; n = 5