Ipragliflozin-induced improvement of liver steatosis in obese mice may involve sirtuin signaling

Figure 1 Body weights and liver-to-body weight ratios of obese mice treated with or without ipragliflozin and their lean littermates. A: Body weights of mice in the lean, obese (ob/ob), ob/ob + ipragliflozin 3 mg/kg, and ob/ob + ipragliflozin 10 mg/kg groups at the end of therapy; B: Liver-to-body weight ratios of mice in the lean, ob/ob, ob/ob + ipragliflozin 3 mg/kg, and ob/ob + ipragliflozin 10 mg/kg groups at the end of therapy. NS: Not significant; ob/ob: Obese; Ipra: Ipragliflozin. n = 8.

Figure 2 Evaluation of liver histology in obese mice treated with or without ipragliflozin and their lean littermates. A: Representative hepatic histology of mice in the lean, obese (ob/ob), ob/ob + ipragliflozin 3 mg/kg, and ob/ob + ipragliflozin 10 mg/kg groups at the end of therapy. The liver sections were stained with Oil Red O; B: Results of quantitative histomorphometric analysis of the total hepatic lipid content for each experimental group. The Oil Red O-stained areas were quantified in 8 microscopic fields at 400-fold magnification. ^bP < 0.01 vs the ob/ob group. ob/ob: Obese; Ipra: Ipragliflozin.

Figure 3 Hepatic sirtuin 1 protein expression in obese mice treated with or without ipragliflozin and their lean littermates. A: Representative western blot showing the expression of hepatic sirtuin 1 (SIRT1) protein at the end of the treatment period; B: The bar graph below shows the expression of SIRT1 normalized to α-tubulin. ^bP < 0.01 vs the ob/ob group. Ipra: Ipragliflozin; ob/ob: Obese; SIRT1: Sirtuin 1; α-TUB: α-tubulin. n = 8.

Figure 4 Hepatic mRNA expression of genes related to sirtuin 1 signaling in obese mice treated with or without ipragliflozin and their lean littermates. A: Hepatic mRNA expression of sirtuin 1 in obese (ob/ob) mice treated with or without ipragliflozin and their lean littermates; B: Hepatic mRNA expression of peroxisome proliferator-activated receptor γ coactivator 1α in ob/ob mice treated with or without ipragliflozin and their lean littermates; C: Hepatic mRNA expression of peroxisome proliferator-activated receptor α in ob/ob mice treated with or without ipragliflozin and their lean littermates; D: Hepatic mRNA expression of fibroblast growth factor-21 in ob/ob mice treated with or without ipragliflozin and their lean littermates; E: Hepatic mRNA expression of fatty acid synthase in ob/ob mice treated with or without ipragliflozin and their lean littermates; F: Hepatic mRNA expression of acetyl-CoA carboxylase in ob/ob mice treated with or without ipragliflozin and their lean littermates. ^aP < 0.05, ^bP < 0.01 vs the ob/ob group. ACC: Acetyl-CoA carboxylase; FAS: Fatty acid synthase; FGF21: Fibroblast growth factor-21; Ipra: Ipragliflozin; NS: Not significant; PPARα: Peroxisome proliferator-activated receptor α; PGC-1α: Peroxisome proliferator-activated receptor γ coactivator 1α; ob/ob: Obese; SIRT1: Sirtuin 1. n = 8.

Figure 5 Hepatic mRNA expression of genes related to β-oxidation, oxidative stress, inflammatory cytokine, and macrophage marker in obese mice treated with or without ipragliflozin and their lean littermates. A: Hepatic mRNA expression of acyl-CoA oxidase 1 in obese (ob/ob) mice treated with or without ipragliflozin and their lean littermates; B: Hepatic mRNA expression of acyl-CoA synthetase in ob/ob mice treated with or without ipragliflozin and their lean littermates; C: Hepatic mRNA expression of carnitine palmitoyltransferase 1 in ob/ob mice treated with or without ipragliflozin and their lean littermates; D: Hepatic mRNA expression of carnitine palmitoyltransferase 2 in ob/ob mice treated with or without ipragliflozin and their lean littermates; E: Hepatic mRNA expression of NADPH oxidase 2 in ob/ob mice treated with or without ipragliflozin and their lean littermates; F: Hepatic mRNA expression of glutathione peroxidase 1 in ob/ob mice treated with or without ipragliflozin and their lean littermates; G: Hepatic mRNA expression of superoxide dismutase 1 in ob/ob mice treated with or without ipragliflozin and their lean littermates; H: Hepatic mRNA expression of superoxide dismutase 2 in ob/ob mice treated with or without ipragliflozin and their lean littermates; I: Hepatic mRNA expression of interleukin-1β in ob/ob mice treated with or without ipragliflozin and their lean littermates; J: Hepatic mRNA expression of F4/80 in ob/ob mice treated with or without ipragliflozin and their lean littermates. ^aP < 0.05, ^bP < 0.01 vs the ob/ob group. NS: Not significant; ob/ob: Obese; Ipra: Ipragliflozin; ACOX1: Acyl-CoA oxidase 1; ACS: Acyl-CoA synthetase; CPT-1: Carnitine palmitoyltransferase 1; CPT-2: Carnitine palmitoyltransferase 2; GPx-1: Glutathione peroxidase 1; IL-1β: Interleukin-1β; Ipra: Ipragliflozin; Nox2: NADPH oxidase 2; SOD-1: Superoxide dismutase 1; SOD-2: Superoxide dismutase 2. n = 8.

Figure 6 Hepatic and renal mRNA expression of sodium glucose cotransporter 2 and phosphorylation of AMP-activated protein kinase in whole livers of obese mice treated with or without ipragliflozin and their lean littermates. A: Reverse transcription-polymerase chain reaction analysis of SGLT2 expression in mouse livers and kidneys; B: Representative western blot showing the levels of phosphorylated phospho-AMP-activated protein kinase (p-AMPK) at the end of the 4-wk period of ipragliflozin treatment; C: The expression of p-AMPK protein was normalized to that of t-AMPK protein. ^aP < 0.05 vs the ob/ob group. Ipra: Ipragliflozin; p-AMPK: Phospho AMP-activated protein kinase; SGLT2: Sodium glucose cotransporter 2; t-AMPK: Total AMP-activated protein kinase. n = 8.