Figure 2.

The effects of Aroclor 1260 exposure and EGF treatment on lipids in liver, blood, and adipose tissue in mice fed HFD. Male WT C57Bl/6 mice were fed an HFD (12 wk) and exposed to either vehicle or Aroclor 1260 ($20\mathrm{mg}/\mathrm{kg}$) by a one-time oral gavage at week 1. Aroclor 1260-exposed or vehicle mice were treated (via IP injection) with saline or EGF ($0.2\mathrm{\mu }\mathrm{g}/\mathrm{g}$) daily for 10 d starting at week 10. Mice were fasted for 12 h and euthanized, and tissues were harvested for downstream analyses. (A) Representative image of H&E staining of liver sections in mice exposed to corn oil and injected with either saline (CS) or EGF ($0.2\mathrm{\mu }\mathrm{g}/\mathrm{g}$) (CE) or gavaged with Aroclor 1260 ($20\mathrm{mg}/\mathrm{kg}$) and injected with saline (AS) or EGF (AE). One liver section per mouse was evaluated ($n=17$ per experimental group). Also included is the quantification from the steatosis grading. Steatosis grading was as follows: $1=\text{normal}$ ($<5\%$), $2=\text{mild}$ (5%–33%), $3=\text{moderate}$ (34%–66%), and $4=\text{severe}$ ($>66\%$). (B) Hepatic measures of (Bi) FFAs, (Bii) TGs, and (Biii) cholesterol. (C) Plasma measures of (Ci) FFAs, (Cii) TGs, and (Ciii) cholesterol. (D) Plasma measures of (Di) HDL, (Dii) LDL, and (Diii) VLDL. (Dv) qPCR analysis of hepatic ApoB gene expression in CS, CE, AS, and AE mice. (E) Weight of epididymal WAT normalized to total body weight (Ei). Plasma measures of adiponectin (Ei) in CS, CE, AS, and AE mice. (F) Illustration demonstrating Aroclor 1260-exposed mice treated with EGF have elevated hepatic TGs and plasma VLDL. An $n=17$ was used for Figures 2A-E. A two-way ANOVA was used to statistically compare data sets followed a Sidak correction for intergroup comparisons. A $p<0.05$ was considered significant. Significance due to EGF is denoted by (a); due to Aroclor 1260 denoted by (b); and due to interaction denoted by (c) for the two-way ANOVA. A $p<0.05$ was denoted by * for the Sidak multiple comparison test. Data are presented as box and whisker plots for Figure 2 that illustrate the median (midline), upper and lower quartiles (box), and the upper and lower limits (whiskers). All numerical data are presented in Table S6 “Numerical Data” as $\text{mean}\pm \text{SD}$ and p-values can be found in Table S5. Numeric outliers were identified by ROUT method and removed. The number of outliers are reported in Table S4. Note: AE, $\text{Aroclor\hspace{0.17em}}1260+\text{EGF}$; ANOVA, analysis of variance; AS, $\text{Aroclor\hspace{0.17em}}1260+\text{saline}$; CE, $\text{control}+\text{EGF}$; CS, $\text{control}+\text{saline}$; EGF, epidermal growth factor; FFAs, free fatty acids; HDL, high-density lipoprotein; H&E, hematoxylin & eosin; HFD, high-fat diet; IP, intraperitoneal; LDL, low-density lipoprotein; TGs, triglycerides; VLDL, very low-density lipoprotein; WAT, white adipose tissue.