Figure 7.
Histologic analysis of rat livers demonstrates dramatic macrophage infiltration and steatohepatitis in cafeteria diet (CAF)-fed rodents. (a–l) ×10 and ×40 hematoxylin and eosin (H&E) stain of liver from (a,e,i) low-fat diet (LFD), (b,f,j) high-fat diet (HFD), (c,g,k) standard chow (SC), and (d,h,l) CAF. Boxes indicate regions magnified to ×40 imaging when appropriate and arrows point to inflammatory loci. Central veins (CV; e–h) and portal triads (PT; i–l) are marked. Note healthy hepatic cord structure in (c) SC-fed livers when compared to macrovessicular steatosis in (i) LFD-fed livers and microvessicular steatotic livers in (j,l) HFD- and CAF-fed rodents. Lipid accumulation in LFD and HFD livers is localized to regions surrounding the (i,j) PT, leaving the (e,f) CV architecture intact, whereas in CAF-fed livers, lipid accumulation is (h,l) panlobular and the (d,h) hepatic cord architecture is disturbed. (m–p) Serial sections relating to images i–l which are stained using macrophage marker F4/80 identify areas of cells aggregating into inflammatory loci (arrows) around the PT in (n) HFD livers and (p) CAF livers (×40). Representative images are shown. (q) Quantification of inflammatory loci in livers revealed a significant 1.5-fold increase in HFD- vs. LFD-fed livers while CAF-fed livers displayed more than fivefold increase (*CAF and HFD P < 0.05 vs. SC). Data are presented as the mean ± s.e.m. (n = 4, SC, LFD, and HFD, n = 5 CAF). See Supplementary Table S4 online for detailed description.