Effects of Sleeve Gastrectomy on Nonalcoholic Fatty Liver Disease in an Obese Rat Model

Laparoscopic sleeve gastrectomy (SG) is an increasingly used bariatric surgery, which is reported to be effective for nonalcoholic fatty liver disease (NAFLD). Recently, activation of farnesoid X receptor (FXR), which is a nuclear receptor of bile acid (BA), was reported to contribute to the resolution of NAFLD. However, it is unclear whether SG has an effect on expression of FXR in the liver. We aimed to investigate the expression of FXR and its related factors in the liver after SG and to clarify the relationship between changes in FXR expression and NAFLD in an obese rat model. Thirty male Zucker fatty rats were divided into three groups: sham-operated (SO) control, pair-fed (PF) control, and SG. Eight weeks after the surgery, metabolic parameters, plasma levels of total BA and liver enzymes, liver triglyceride (TG) content, and mRNA expression of FXR and its related factors, such as small heterodimer partner (SHP) and peroxisome proliferator-activated receptor alpha (PPAR alpha), were measured. Metabolic parameters in the SG group were significantly improved compared with the SO group. Liver enzymes and TG were significantly lower in the SG group than in the SO group. Plasma levels of BA were significantly higher in the SG group than in the SO and PF groups. mRNA expression of FXR, SHP, and PPAR alpha in the liver was significantly higher in the SG group than in the SO group. These results suggest that the effects of SG on NAFLD should be associated with the expression of the FXR pathway in the liver in a Zucker fatty rat model.