Comparison of conjugated linoleic acid and linoleic acid on cytotoxicity, synthesis, and secretion of lipids in HepG2 cells

The present study was undertaken to compare the effects of conjugated linoleic acid (CLA) and Linoleic acid (CLA) on cytotoxicity, synthesis, and secretion of Lipids in Hep G2 cells. The cells were grown in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS), and treated with 50, 100, 250, 500, and 1000 muM of CLA and LA for 24 h. At concentrations up to 250 muM, no significant cytotoxic effect was found in either fatty acid. At concentrations above 500 muM, the cell viability decreased significantly compared to the control (p < 0.05), but no significant differences were noted between CLA and LA. The treatment of cells with 100 <mu>M (noncytotoxic concentration) of CLA and LA significantly increased H-3-acetate incorporation into cholesterol compared to the nontreated control, but no significant difference was noted between CLA and LA, The treatment of cells with CLA and LA also stimulated H-3-glycerol incorporation into triglyceride and, phospholipid in cells and their secretion into the medium, and triglyceride synthesis in cells was significantly higher with CLA than LA (p < 0.05). The fatty acid composition of cellular lipids revealed that CLA was enriched more in triglyceride than in cholesteryl ester or phospholipid, and CLA appeared to be a less preferred substrate for phospholipid synthesis compared to LA (3.8 vs, 14.9%).