BackgroundA high-fat diet (HFD) is known to lead to obesity, and contributes to the progression of non-alcoholic fatty liver disease. The objective of this study was to evaluate the effects of sleeve gastrectomy (SG) on the progression of HFD-induced hepatic steatosis.MethodsFifteen 4-week-old, male Wistar rats were randomly assigned into three groups: NC, HFD+SHAM and HFD+SG. Their body weight, glucose-lipid metabolism, inflammation indices, hepatic steatosis and fibroblast growth factor 21 (FGF21) levels were measured.ResultsPostoperatively, body weights in the HFD+SHAM and HFD+SG group rats decreased during the first week. Thereafter, HFD+SG rats regained their body weight. Differences in insulin, homeostasis model assessment of insulin resistance, triglyceride, free fatty acid, tumor necrosis factor- and monocyte chemotactic protein-1 levels were statistically significant across the three groups (all P<0.05). Interestingly, FGF21 levels in the HFD+SG group were markedly lower than in the HFD+SHAM group (P=0.015), however, there were no differences in the NC group. Hematoxylin and eosin staining demonstrated that more vacuoles were present in the HFD+SHAM liver when compared to the HFD+SG liver. Oil-red O staining showed less red dots in the HFD+SG liver.ConclusionsDespite eating, surgical re-routing of the gut may prevent weight accumulation, regulate glucose-lipid metabolism and insulin sensitivity, control a chronic inflammatory state, change the secretion pattern of FGF21 and alleviate the severity of fatty liver.