Empagliflozin alleviates podocytopathy and enhances glomerular nephrin expression in db/db diabetic mice

Figure 1 Design of the experiment. The db/db diabetic mice were randomized into vehicle and empagliflozin groups. Heterozygous non-diabetic db/+ mice were included as controls. The studied drug or vehicle was administered by gavage once per day from 8 to 16 wk of age. Procedure 1 at wk 8: Weight measurement, body composition assessment, blood and urine sampling. Procedure 2 at wk 12: Weight measurement, body composition assessment, blood sampling. Procedure 3 at wk 16: Weight measurement, body composition assessment, blood and urine sampling, sacrifice and kidney sampling. EMPA: Empagliflozin.

Figure 2 Urinary albumin-to-creatinine ratio at week 0 and week 8 of the experiment in non-diabetic db/+ mice and diabetic db/db mice, treated with vehicle or empagliflozin. The data are presented as medians, lower and upper quartiles. ^aP < 0.001 vs non-diabetic control (db/+ mice); ^bP < 0.001 vs placebo(Mann-Whitney U-test); ^cP < 0.01 vs week 8 (Wilcoxon test). EMPA: Empagliflozin.

Figure 3 Podocyte foot processes. A: Non-diabetic db/+ mice; B: Vehicle-treated db/db diabetic mice demonstrate effacement of podocyte foot processes(FPs); C: Empagliflozin restores the structure of FPs in db/db mice. Transmission electron microscopy: ×100000.

Figure 4 Glomerular staining for nephrin. A:Non-diabetic db/+ mice; B: Vehicle-treated db/db mice; C: Empagliflozin-treated db/db mice; A-C: Immunohistochemistry with anti-nephrin antibody; D: Negative control.

Figure 5 Glomerular staining for TGF-β. A:Non-diabetic db/+ mice; B: Vehicle-treated db/db mice; C: Empagliflozin-treated db/db mice; A-C: Immunohistochemistry with anti-TGF-β antibody; D: Negative control.

Figure 6 Volumetric density of nephrin-positive areas and TGF-β-positive areas in glomeruli of nondiabetic db+ and diabetic EMPA-treated and vehicle-treated db/db mice. A: Nephrin-positive areas; B: TGF-β-positive areas. ^aP < 0.001 vs non-diabetic db/+ mice; ^bP < 0.01; ^cP < 0.001 vs vehicle treated db/db mice (Wilcoxon test). Vv: Volumetric density; TGF-β: Transforming growth factor β; EMPA: Empagliflozin.