Deficiency of apoA-IV in Female 129X1/SvJ Mice Leads to Diet-Induced Obesity, Insulin Resistance, and Decreased Energy Expenditure

Figures

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  Figure 1. The progression of obesity in apoA-IV−/− mice over a 16-week HFD study. (A) Body weight. (B) Body weight change. Data are depicted as mean ± SEM (n = 6) and analyzed statistically via regular two-way ANOVA. Significant differences relative to the WT group (* p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001).

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  Figure 2. ApoA-IV−/− mice conferred greater adiposity than WT mice. Body composition with the percentage of fat (A) and lean (B) mass. (C) Percentage of periovarian, subcutaneous, and retroperitoneal white adipose tissues (WAT) and brown adipose tissue (BAT) in mice at the end of 16-week HFD study. (D) The size distribution of adipocytes in H&E staining of periovarian fat pads collected during animal sacrifice. Data are presented as mean ± SEM (n = 6) and analyzed statistically via regular two-way ANOVA. Significant differences relative to the WT group (* p < 0.05; ** p < 0.01; **** p < 0.0001).

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  Figure 3. ApoA-IV−/− mice contained higher leptin levels and comparable adiponectin levels than WT mice at the end of the 16-week HFD study. (A) Leptin levels. (B) Adiponectin levels. Black circles indicate WT mice and white circles indicate ApoA-IV−/− mice. Data are depicted as mean ± SEM (n = 6) and analyzed statistically via student t-test. Significant differences compared to the WT group (* p < 0.05).

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  Figure 4. Lipid profile analysis of WT and apoA-IV−/− mice at the end of 16-week HFD study. (A) Circulating triglycerides (TG) levels. (B) Cholesterol levels. (C) Phospholipids levels. (D) Non-esterified fatty acid (NEFA) levels. Black circles indicate WT mice and white circle indicate ApoA-IV−/− mice. Data are depicted as mean ± SEM (n = 6) and analyzed statistically via student t-test. Significant differences relative to the WT group (* p < 0.05; *** p < 0.001).

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  Figure 5. Glucose tolerance test in WT and apoA-IV−/− mice before and during HFD study. Blood glucose levels over 120 min upon glucose challenge at 0 (A) and weeks 4 (B), 8 (C), 12 (D), and 16 (E) of the HFD study. Data are presented as mean ± SEM (n = 6), and statistical analysis of data was conducted via regular two-way ANOVA. Significant differences relative to the WT mice group (* p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001).

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  Figure 6. Plasma insulin levels during glucose tolerance test in WT and apoA-IV−/− mice before and during HFD study. Plasma insulin levels throughout 120 min post-post-glucose injection), before (A) and on weeks 4 (B), 8 (C), 12 (D), and 16 (E) of the HFD study. Data are presented as mean ± SEM (n = 6), and statistical analysis of data was conducted via regular two-way ANOVA. Significant differences relative to the WT group (* p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001).

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  Figure 7. Glucose homeostasis in WT and apoA-IV−/− mice during 16-week HFD study. (A) Blood glucose levels. (B) Plasma insulin levels. (C) HOMA-IR. Data are presented as mean ± SEM (n = 6) and analyzed statistically via regular two-way ANOVA. Significant differences relative to the WT group (* p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001).

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  Figure 8. Food intake and energy expenditure of WT and apoA-IV−/− mice during a 16-week HFD study. (A) Weekly food intake. Average heat production over 12-h and 24-h time course (B,C), average respiration quotient over 12-h and 24-h time course (D,E), and cumulative physical activity over 24-h (F,G) on Weeks 8 and 16, respectively, after HFD consumption. Data are presented as mean ± SEM (n = 6). Data in (A,F,G) were analyzed statistically via regular two-way ANOVA, whereas data analysis in (B–E) were determined statistically via student t-test. Significant differences relative to the WT group (* p < 0.05; ** p < 0.01).