Conjugated linoleic acid isomers modulate protein expression profile in rat hepatocytes

Conjugated linoleic acid (CLA) is a polyunsaturatedfatty acid, which has been recently proven to beeffective in reducing body fat mass, but brings as a sideeffect, the liver enlargement due to an increased lipidcontent. The in vivo lipogenic activity has been suggestedto be due to the reduction in fat mass and to the consequentmetabolism of blood glucose to fatty acid in the liver ratherthan in the adipose tissue. We investigated the ability ofCLA to directly induce steatosis by modulating theexpression pattern of hepatic proteins involved in lipidmetabolism. To avoid interferences derived from CLAmetabolism by other tissues, we used the in vitro model offreshly isolated rat hepatocytes incubated in the presence ofdifferent CLA isomers. The direct effect of CLA on lipidaccumulation in hepatocytes was demonstrated by thealtered expression pattern of several proteins involved inlipid metabolism, as assessed by two-dimensional gelelectrophoresis and confirmed by Western blotting analysis.The CLA isomer c9,t11 was most effective in modulatingthe protein expression profile.