Targeting Sirt1 in a rat model of high-fat diet-induced non-alcoholic fatty liver disease: Comparison of Gegen Qinlian decoction and resveratrol

The present study aimed to explore the mechanism of action of Gegen Qinlian decoction (GGQLD) in experimental non-alcoholic fatty liver disease (NAFLD). A total of 30 rats were randomly divided into five groups: The chow, model, high- and low-dose GGQLD (GGQLD-H and GGQLD-L, respectively) and resveratrol (Resl) groups, and were treated with saline, GGQLD and Resl when a model of high-fat diet (HFD)-induced NAFLD was established. Blood lipid and liver enzymes were detected following treatment for 8 weeks and liver tissue pathology was observed using Oil Red O and haematoxylin and eosin staining. Furthermore, the liver protein and mRNA expression of sirtuin (Sirt)1, peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) were measured using western blotting and reverse transcription-quantitative polymerase chain reaction. Compared with the chow group, the model group demonstrated significantly increased serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels (P<0.01). GGQLD doses and Resl attenuated the elevated serum ALT and AST levels. GGQLD-H and Resl significantly increased the serum high-density lipoprotein cholesterol level compared with that in the model group (P<0.01), while GGQLD-L and Resl significantly decreased serum low-density lipoprotein cholesterol levels (P<0.01). The GGQLDs and Resl groups revealed an evident improvement in Sirt1 protein and mRNA expression. Although GGQLD and Resl significantly decreased NF-κB gene expression compared with the model group (P<0.01), the effect on NF-κB protein expression was not significant. Furthermore, the PGC-1α gene and protein expression in the HFD rat group slightly decreased compared to the levels in the chow group, but the decrease was insignificant. However, an evident increase in PGC-1α mRNA expression was observed in the GGQLD-H group compared with the model group (P<0.01). Histological staining revealed that GGQLD and Resl decreased the lipid droplets in hepatocytes and normalized steatosis in rats fed with a HFD. The results indicated that GGQLD treatment may be a potent strategy for managing NAFLD by managing lipid metabolism and inflammatory and histological abnormalities by triggering the Sirt1 pathway.