Effect of resveratrol on experimental non-alcoholic fatty liver disease depends on severity of pathology and timing of treatment.

BACKGROUND AND AIM Non-alcoholic steatohepatitis (NASH) is a leading cause of chronic liver disease with few therapeutic options. Resveratrol (RSV) prevents the development of steatosis in a number of experimental fatty liver (non-alcoholic fatty liver [NAFL]) models, but the preventive or therapeutic effects on experimental NASH are not yet clarified, and clinical results on non-alcoholic fatty liver disease are ambiguous. Thus, we aimed to compare the RSV-mediated preventive and therapeutic effects on experimental NAFL and NASH. METHODS We used a high-fat (HF) diet to generate a rat NAFL model and a high-fat, high-cholesterol (HFC) diet to generate a rat NASH model. The preventive and therapeutic potential of RSV was tested by adding RSV to the HF and HFC diet from study start or after 1 week of the diets. Animals were sacrificed after 8 weeks with appropriate controls. Blood and liver were harvested for analysis, including measurement of RSV metabolites. RESULTS Resveratrol reduced the development of histological steatosis (P = 0.03) and partly triglyceride accumulation (fold change reduced from 3.6 to 2.4, P = 0.08) in the male NAFL model, although effects were moderate. In NASH prevention, RSV reduced the accumulation of triglyceride in hepatic tissue (P < 0.01), while there was no effect on biochemical, histopathological, or transcriptional NASH changes. Further, RSV had no therapeutic effect on established NASH. We found RSV metabolites but no parent RSV in serum or liver tissue, confirming low bioavailability. CONCLUSIONS These experimental findings suggest that a weak hepatic benefit of RSV treatment is seen in prevention of steatosis only.