Fig 1.
Effect of lobeglitazone (Lobe) on body weight and food intake in high-fat diet (HFD)-fed mice.
Mice were fed Lobe (1 or 5 mg/kg/d) for 9 weeks (n = 8 per group). (A) Body weight, (B) food intake, (C) fat and lean mass, (D) representative photographs of intraabdominal organs, and (E) organ weights for each group at the time of sacrifice (18 weeks of age). Data are presented as mean ± SEM. *P <0.05 vs. normal diet (ND)-fed mice; †P <0.05 vs. HFD-fed mice. Scale bar = 1 cm.
Fig 2.
Effect of lobeglitazone (Lobe) on insulin resistance in high-fat diet (HFD)-fed mice.
(A) Serum glucose, (B) serum insulin, (C) homeostatic model assessment of insulin resistance (HOMA-IR), (D) glucose tolerance test, and (E) insulin tolerance test in normal diet (ND), non-treated HFD, Lobe-treated (1 or 5 mg/kg/d) HFD, and Lobe-only mice. (F) Representative microphotographs of immunostained insulin in pancreatic sections from each group. Scale bar = 100 μm. Western blot for (G) glucose transporter 4 (GLUT4) and (H) insulin receptor (IR) expression in the liver for each group. Quantification of GLUT4 and IR expression from western blot analysis. Densitometry values are normalized to β-actin and represented as arbitrary units. (I) Serum lipocalin-2 concentrations obtained by enzyme-linked immunosorbent assay. Data are presented as mean ± SEM. *P <0.05 vs. ND-fed mice; †P <0.05 vs. HFD-fed mice. AUC, area under the curve.
Fig 3.
Effect of lobeglitazone (Lobe) on hepatic steatosis in high-fat diet (HFD)-fed mice.
(A) Hematoxylin and eosin and Nile Red staining of hepatic lipid accumulation, (B) percentage of lipid droplets in Nile Red-stained sections, (C) hepatic triglyceride (TG) concentration, and (D) serum hepatic enzymes in normal diet (ND), non-treated HFD, Lobe-treated HFD (1 or 5 mg/kg/d), and Lobe-only mice. *P <0.05 vs. ND-fed mice; †P <0.05 vs. HFD-fed mice.
Fig 4.
Effect of lobeglitazone (Lobe) on hepatic lipogenesis in high-fat diet (HFD)-fed mice.
Western blots and quantification of hepatic (A) peroxisome proliferator-activated receptor (PPAR) α, (B) PPARγ, (C) fatty acid synthase (FAS), (D) stearoyl-CoA desaturase (SCD) 1, (E) diglyceride acyltransferase (DGAT) 1, and (F) carbohydrate response element binding protein (ChREBP)-1 expression in normal diet (ND), non-treated HFD, Lobe-treated HFD (1 or 5 mg/kg/d), and Lobe-only mice. Densitometry values for each protein are normalized to β-actin or p84. Data are presented as mean ± SEM. *P <0.05 vs. ND-fed mice; †P <0.05 vs. HFD-fed mice.
Fig 5.
Partial least squares-discriminant analysis (PLS-DA) scores scatter plots of liver (A and B) and serum (C and D) metabolites analyzed using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry and (UPLC-Q-TOF MS) and heat maps of identified hepatic (E) and serum (F) metabolites. Differences among all sample groups (A; liver, C; blood) and sample groups of ND, HFD, and HFD+ lobeglitazone 5 mg (B; liver, D; blood) were visualized respectively by PLS-DA scores scatter plots. The quality of the PLS-DA models were evaluated by the goodness of fit (R2X and R2Y) and predictive ability (Q2Y), and validated by a 7-fold cross validation with a permutation test (n = 200). All sample groups were visualized by Heat maps of identified hepatic (E) and serum (F) metabolites obtained using UPLC-Q-TOF MS. The heat maps were drawn using R with ggplot2, and the red-blue colors represent the z-score transformed raw data of serum and hepatic metabolites with significant differences among groups. Red and blue indicate decreases and increases in metabolite levels, respectively. HFD, high-fat diet; Lobe, lobeglitazone; LPC, lysophosphatidylcholine; ND, normal diet.
Fig 6.
Effect of lobeglitazone (Lobe) on serum leptin and hypothalamic signaling transducer and activator of transcription 3 (STAT3) and proopiomelanocortin (POMC) 2 expression in HFD-fed mice.
(A) Serum leptin concentrations and (B) western blot and quantification of p-STAT3 and total STAT3 in the hypothalamuses from each group. Densitometry values for each protein are normalized to total STAT3. (C) Representative microphotographs of immunostained POMC-positive cells in the arcuate nucleus of hypothalamuses from each group. Asterisks indicate POMC-positive neurons. Scale bar = 50 μm. (D) The number of POMC-positive cells. Data are presented as mean ± SEM. *P <0.05 vs. ND-fed mice; †P <0.05 vs. HFD-fed mice. HFD, high-fat diet; Lobe, lobeglitazone; ND, normal diet.