Caffeine affects HFD-induced hepatic steatosis by multifactorial intervention.

The incidence of nonalcoholic fatty liver disease (NAFLD) is considered a risk factor for hepatic fibrosis. Therefore, there is critical need to develop novel cheap and effective therapeutic approaches to prevent and reverse NAFLD. Caffeine is commonly consumed beverage and has antioxidant and anti-inflammatory activities. This study examined whether caffeine can ameliorate liver injury induced by high-fat diet (HFD) feeding. Four groups of rats were used and treated for 16 weeks as follows: control group, rats were fed a standard diet; HFD group, rats were fed HFD; and caffeine 20 and caffeine 30 groups, rats were fed HFD for 16 weeks in addition to different doses of caffeine (20 or 30 mg/kg, respectively) for last 8 weeks. The HFD-induced liver injury is determined biochemically by evaluating serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, bilirubin, triglycerides, cholesterol, and high-density lipoprotein-cholesterol and by histopathological examination. Tissue malondialdehyde, total nitrate/nitrite, and glutathione concentration were also measured. Real-time reverse transcription polymerase chain reaction technique was used to determine the expression of lipogenic enzyme genes. Caffeine treatment significantly decreased the elevated serum ALT, AST, and bilirubin and increased the reduced albumin level. Interestingly, the hepatic mRNA expression of Fatty acid synthase and acetyl CoA carboxylase was decreased by caffeine, while the protein expression of hepatic carnitine palmitoyltransferase 1 and proliferation-activated receptor α was increased. Furthermore, caffeine reduced tissue lipid peroxidation and oxidative stress. These effects suggest that caffeine could improve HFD-induced hepatic injury by suppressing inflammatory response and oxidative stress and regulating hepatic de novo lipogenesis and β-oxidation.