Effect of conjugated linoleic acid on bovine mammary cell growth, apoptosis and stearoyl Co-A desaturase gene expression.

Abstract The effects of the primary biologically active conjugated linoleic acid (CLA) isomers ( cis -9, trans -11 and trans -10, cis -12; 15–150 μM) on growth and survival of the bovine mammary cell-line, Mac-T, were evaluated using cell enumeration and TUNEL assay. Previous studies have shown that high concentrations of CLA induced severe milk fat depression and have had negative effects on milk yield and composition whereas the impact of lower doses has been a modest depression in milk fat percent. In this study, we show that increasing concentrations of both CLA isomers had negative impacts on cell growth, including reduced cell number at concentrations of 35 μM and above ( P stearoyl Co-A desaturase ( Scd ) gene promoter was also analyzed. While a significant difference in the Scd promoter transcriptional activity was not observed in cells treated with different concentrations of CLA, insulin significantly enhanced Scd promoter activity in CLA-treated cells. Our in vitro data support the hypothesis that high levels of CLA may induce in vivo apoptosis in the mammary gland.