Metabolic impact of trans 10, cis 12-conjugated linoleic acid on pai transgenic mice

Abstract

Trans 10, cis 12-conjugated linoleic acid (t10c12-CLA) from ruminant-derived foodstuffs can induce body fat loss in mammals after oral administration, while its mechanism on fat reduction has yet to be clarified fully until now. In the current study, a transgenic mouse that produced t10c12-CLA had been generated by inserting the Propionibacterium acnes isomerase (Pai) expression cassette into the Rosa26 locus, and its male offspring were used to decipher an irreversible long-term impact of t10c12-CLA on health and its mechanism of action. Compared to their wild-type C57BL/6J littermates, comprehensive phenotype profiling of biallelic pai/pai mice indicated that white fat was decreased while brown fat was increased reversely; meanwhile, more heat was released and the central activities were reduced. Besides decreased plasma triglycerides in both pai genotypes and increased serum FGF21 in pai/wt mice, RNA and protein analysis revealed that the fatty acid oxidation and thermogenesis capacity of brown adipose tissues were elevated via CPT1B and UCP1/2 over-expression. The results indicate that the t10c12-CLA-induced fat loss might be caused by the excess FGF21 and the increased mass and extra thermogenesis of brown adipose tissue in transgenic mice.