Objective To observe the effect of blueberry anthocyanin on the expression of Plin5 in mice with hepatocyte steatosis induced by oleic acid, and to elucidate its possible mechanism.Methods The AML12 (alpha mouse liver 12) hepatocytes were cultured and the exponential phase cells were then divided into control group, oleic acid-induced group, vitamin C group, and blueberry anthocyanin group, each tested in triplicate. The cells in the control group were cultured in DMEM/F12 medium, while those in the oleic acid-induced group, vitamin C group, and blueberry anthocyanin group were treated with the medium containing 0.75 mmol/L oleic acid for 24 h to establish cell models of hepatocyte steatosis. After successful modeling, water-soluble vitamin C with antioxidant activity was used as the positive control drug, and the cells in the vitamin C group and blueberry anthocyanin group were treated with the medium containing 50 μg/ml vitamin C and 50 μg/ml blueberry anthocyanin for another 24 h, respectively. The levels of alanine transaminase (ALT) and aspartate aminotransferase (AST) in the supernatant of the cell culture medium and the intracellular triglyceride (TG) content in each group were determined by the microplate-reader method. The lipid droplet deposition in the cells was observed by oil red O staining. The expression of Plin5, PI3K, and P-Akt in AML12 cells was detected by Western blotting.Results The cell index in the groups treated with 100 μg/ml, 150 μg/ml, and 200 μg/ml blueberry anthocyanin was lower than that in the group without the treatment of blueberry anthocyanin (P 0.05). The inhibition rate was 14.4% in the group treated with 100 μg/ml blueberry anthocyanin, but the inhibitory effect was slight when the concentration of blueberry anthocyanin was 50 μg/ml. Compared with the control group, the levels of ALT and AST, the intracellular TG content, the integrated optical density (IOD) of the lipid droplets, and the expression levels of Plin5, PI3K, and P-Akt proteins in the oleic acid-induced group were increased (P < 0.05). Compared with the oleic acid-induced group, the levels of ALT and AST, the intracellular TG content, the IOD of lipid droplets, and the expression levels of Plin5, PI3K, and P-Akt proteins in the vitamin C group and blueberry anthocyanin group were decreased (P < 0.05). Compared with the vitamin C group, the levels of ALT and AST, the intracellular TG content, the IOD of lipid droplets, and the expression levels of Plin5 and PI3K proteins in the blueberry anthocyanin group were even decreased (P < 0.05).Conclusions Blueberry anthocyanin ameliorates the hepatocyte steatosis induced by oleic acid in mice to some extent. The underlying mechanisms may be related to the inhibition of the expression of Plin5 regulated via PI3K/Akt signaling pathway and the reduce in the formation of lipid droplets induced by oleic acid in the hepatocytes.