Effects of High Zinc Levels on the Lipid Synthesis in Rat Hepatocytes

Abstract

Zinc deficiency impairs the hepatic lipid metabolism. Previous studies were focused on the negative effects of zinc deficiency on the hepatic lipid metabolism. A few studies investigated the effects of high zinc levels on the lipid metabolism in hepatocytes. In this study, rat hepatocytes were cultured and treated with different and high concentrations of zinc to investigate the effects of high zinc levels on the lipid synthesis in hepatocytes in vitro. The levels of hepatocytes functional markers, including alkaline phosphatase, lactate dehydrogenase, and albumin, were significantly higher in the zinc treatment groups than in the control group (p < 0.05, p < 0.01). The mRNA and protein levels of sterol regulatory element-binding protein 1c (SREBP-1c) were significantly higher in the zinc treatment groups than in the control group (p < 0.05, p < 0.01). Furthermore, the mRNA expression levels of acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase (FAS) were significantly higher in the medium- and high-dose zinc treatment groups than in the control group (p < 0.01). The mRNA levels of stearoyl-CoA desaturase-1 (SCD-1) were significantly higher in the high-dose group (p < 0.01). These results indicate that high levels of zinc increase hepatocytes activity and SREBP-1c expression, which upregulate the expression of ACC1, FAS, and SCD-1, thereby improving the lipid metabolism in the hepatocytes.