Figure 3
Glucose-lowering effects of dapagliflozin on retinal adiponectin and vascular permeability in streptozotocin-induced diabetic mice. (A) After the onset of streptozotocin (STZ)-induced diabetes (Day 1), 8-week-old male wild-type (WT) mice were treated with vehicle (STZ/Vehi) or dapagliflozin (STZ/Dapa) for 6 weeks. To evaluate retinal vascular permeability, a mixed solution of Hoechst and fluorescein isothiocyanate (FITC)-dextran was transcardially injected into each mouse, and retinas were removed at 5 min after injection. Mice without STZ injection were also analyzed as a control (Cont). (B, C) Changes in body weights (B) and blood glucose levels under 4-h fasting conditions (C). n = 14 for Cont, n = 19 for STZ/Vehi, and n = 18 for STZ/Dapa. Data are the mean ± SEM; ***P < 0.001 vs Cont and †††P < 0.001 vs STZ/Vehi (one-way ANOVA with Tukey’s post hoc test). (D) Plasma adiponectin (APN) concentrations at day 35. n = 14 for Cont, n = 15 for STZ/Vehi, and n = 16 for STZ/Dapa. Data are the mean ± SEM; N.S., not significant (one-way ANOVA with Tukey’s post hoc test). (E) Representative images of retinal whole-mount immunofluorescence staining for APN (red) and CD31 (gray). Scale bar = 100 μm. (F) The % area of the APN-positive region in CD31-positive endothelium. Quantification was performed using two randomly obtained sections for each mouse. n = 6 for Cont, n = 7 for STZ/Vehi, and n = 8 for STZ/Dapa. Data are the mean ± SEM; *P < 0.05. N.S., not significant (one-way ANOVA with Tukey’s post hoc test). (G) Representative immunofluorescence images for Hoechst (red) and FITC-dextran (green). Scale bar = 100 μm. (H) Extravascular Hoechst-positive cell numbers (left) and % area (right) were calculated using two randomly obtained sections for each mouse. n = 8 for Cont, n = 12 for STZ/Vehi, and n = 10 for STZ/Dapa. Data are the mean ± SEM; *P < 0.05 and **P < 0.01. N.S., not significant (one-way ANOVA with Tukey’s post hoc test).
