Serum c-reactive protein concentration was also measured using a rat c-reactive
protein enzyme-linked immunosorbent assay kit obtained from BD Biosciences (San Diego, CA) following the manufacturer’s instructions. Groups of data were compared using analysis of variance followed by Tukey’s multiple comparison tests. P < 0.05 was considered statistically significant. The mean daily energy intakes of HFD-fed rats were 15% higher than those of control rats (75 ± 4 kcal/die versus 65 ± 2 kcal/die). AG14699 A 22% average higher weight gain in HFD-fed rats versus control rats (365 ± 4 g versus 300 ± 3 g, respectively) was recorded from the 10th week of feeding through the end of the study. No difference in weight gain was found among HFD-fed rats drinking coffee, polyphenols, melanoidins or water. No significant differences were found among treatment groups for the concentrations of aspartate
aminotransferase, Wnt signaling alkaline phosphatase, and γ glutamyl transpeptidase. Total cholesterol was not statistically different in HFD + water versus control rats (67.8 ± 4.9 mg/dL versus 51.2 ± 2.0 mg/dL [P value not significant]) and a concentration close to that of control animals was found in the HFD + coffee group (56.3 ± 2.6 mg/dL [P value not significant]). Serum concentrations of high-density lipoprotein and low-density lipoprotein cholesterol were not different in HFD + water versus control rats (19.4 ± 2.3 mg/dL versus 16.6 ± 3.6 mg/dL and 10.5 ± 6.3 mg/dL versus 13.4 ± 8.2 mg/dL, respectively [P value not significant]) as well as versus HFD + coffee (14.6 ± 2.9 mg/dL and 16.5 ± 0.7 mg/dL, respectively), HFD + polyphenols (19.0 ± 3.3 mg/dL and 12.0 ± 1.4 mg/dL, respectively), and HFD + melanoidins (15.8 ± 3.6 mg/dL and 16.0 ± 1.3 mg/dL, respectively). Serum triglyceride and ALT levels were significantly increased in HFD-fed rats compared with controls. A significant reduction of triglycerides was found only in rats treated with coffee or melanoidins (Fig. 1A), whereas a reduction of serum ALT concentration was
found with both coffee and not the two components (Fig. 1B). Hematoxylin-eosin and Sirius red staining in livers of normal rats are shown in Fig. 2A and 2B, respectively. Steatosis affected a large number of hepatocytes, with the presence of diffuse ballooning and foci of inflammatory cell infiltration present throughout the lobule (Fig. 2C). Both the presence of lipid droplets and the inflammatory infiltrate were significantly reduced by coffee, polyphenols, or melanoidins (Fig. 2E). Sirius red staining in HFD rats revealed the presence of red-stained collagen fibers (Fig. 2D) as an index of hepatic fibrosis. The fibrotic septa significantly regressed after intake of coffee, polyphenols, or melanoidins (Fig. 2F). According to liver inflammation and collagen deposition in fibrotic septa, as evidenced by histology, TNF-α and tissue transglutaminase (tTG) expressions were higher in HFD-fed rats than in control rats (Fig. 3A,B).