Low level of trans-10, cis-12 conjugated linoleic acid decreases adiposity and increases browning independent of inflammatory signaling in overweight Sv129 mice

The objective of this study was to determine the extent to which a low level of trans-10, cis-12 (10,12) conjugated linoleic acid (CLA) decreases adiposity and increases browning in overweight mice, its dependence on inflammatory signaling and potential synergistic effects of daily exercise. Young, Sv129 male mice were fed a high-fat diet for 5 weeks to make them fat and glucose intolerant and then switch them to a low-fat diet with or without 0.1% 10,12 CLA, sodium salicylate or exercise for another 7 weeks. 10,12 CLA decreased white adipose tissue (WAT) and brown adipose tissue mass, and increased the messenger RNA and protein levels, and activities of enzymes associated with thermogenesis or fatty acid oxidation in WAT. Mice fed 10,12 CLA had lower body temperatures compared to controls during cold exposure, which coincided with decreased adiposity. Although sodium salicylate decreased 10,12 CLA-mediated increases in markers of inflammation in WAT, it did not affect other outcomes. Exercise had no further effect on the outcomes measured. Collectively, these data indicate that 10,12 CLA-mediated reduction of adiposity is independent of inflammatory signaling, and possibly due to up-regulation of fatty acid oxidation and heat production in order to regulate body temperature. Although this low level of 10,12 CLA reduced adiposity in overweight mice, hepatomegaly and inflammation are major health concerns.