Glycyrrhizin Improves Fatty Liver Symptoms, Increases Adiponectin and Reduces UCP2 Expression in Wistar Rats

Glycyrrhizin (GL) is the main bioactive component in the extract of licorice root, with beneficial effects on metabolic syndrome. This study investigates the effect of GL on biochemical and histological parameters and UCP2 gene expression in a rodent nonalcoholic steatosis model. Thirty-two male Wistar rats were classified into four groups randomly: control (normal diet with standard rat chow), high-cholesterol diet (HCD for 12 weeks) and two experimental groups (HCD for 12 weeks then shifted to normal diet plus receiving either 20 mg/kg or 100 mg/kg of glycyrrhizin for 4 weeks). At the end of experiment, in the HCD group, body weight, glucose and insulin levels were increased, lipid profile was impaired, and the markers related to liver were abnormal, while adiponectin, catalase and superoxide dismutase levels were decreased. Histological analysis of liver sections showed the appearance of hepatic fibrosis and steatosis, and UCP2 gene expression was increased significantly. GL treatment at both doses and especially at 100 mg/kg ameliorated the situation, and levels of UCP2 were decreased significantly. In conclusion, administration of glycyrrhizin can improve liver fibrosis through down-regulating the UCP2 expression.