Objective        To study the effect of different dietary fatty acid compositions on expression of sterol-regulatory elementary binding protein-1c (SREBP-1c) and lipid metabolism in hepatic cells.       Methods        HepG2 cells were divided into control group

eicosapntemacnioc acid (EPA) group

palmitic acid (PA) group

1∶1 EPA and linoleic acid (LA) mixture group

1∶1 PA and oleic acid (OA) mixture group. The final concentration of EPA and LA was 150 μmol/L in EPA group and PA group respectively

and 75 μmol/L in EPA and LA mixture group and PA and OA mixture group respectively. The total concentration was 150 μmol/L 24 h after the HepG2 cells were treated. Changes of lipid droplet and its level in HepG2 cells were observed with oil red staining. Expression level of SREBP-1c mRNA and protein was measured by RT-PCR and Western blotting respectively.       Results        The expression level of SREBP-1c mRNA and protein was significantly higher in PA group and 1∶1 PA and OA mixture group

and significantly lower in EPA group and 1∶1 EPA and LA mixture group than in control group (P0.05). The lipid level in hepatic cells was significantly lower in EPA group and 1∶1 EPA and LA mixture group than in control group (P0.05)

and significantly higher in PA group and 1∶1 PA and OA mixture group (P0.05).       Conclusion        PA and OA up-regulate the expression of SREBP-1c and promote the synthesis of lipid by promoting the fatty degeneration in hepatic cells

while EPA and LA down-regulate the expression of SREBP-1c and decrease the lipid level by reducing the fatty degeneration in hepatic cells.