Long-term dietary DHA intervention prevents telomere attrition and lipid disturbance in telomerase-deficient male mice.

Abstract

Previous evidence indicated anti-ageing potential of docosahexaenoic acid (DHA), but the underlying mechanism remains unclear. We investigated protective effect of DHA on telomere attrition and lipid disturbance in male mice with premature ageing caused by telomerase deficiency. Wild-type (WT) and fourth-generation telomerase-deficient (G4 Terc-/-, Terc knockout, KO) male mice (C57BL/6, 2months old) were fed control diet (WT-C and KO-C groups) or DHA-enriched diet containing 0.80% DHA by weight (WT-DHA and KO-DHA groups) for 10months. The ageing phenotypes and metabolic level [carbon dioxide emission, oxygen consumption, and respiratory exchange ratio (RER)] were assessed at the end of the experiment. Telomere length in various tissues and the hepatic gene and protein expression for regulating lipid synthesis and lipolysis were measured. Data were tested using one- or two-factor ANOVA. In KO male mice, DHA prevented weight loss, corrected high RER, and reduced fat loss. Telomere shortening was reduced by 22.3%, 25.5%, and 13.5% in heart, liver, and testes of the KO-DHA group compared with those in the KO-C group. The KO-DHA group exhibited higher gene transcription involved in glycerol-3-phosphate pathway [glycerol-3-phosphate acyltransferase (Gpat)], lower gene expression of β-oxidation [carnitine palmitoyltransferase 1a (Cpt1a)], and upregulation of proteins in lipid synthesis [mammalian target of rapamycin complex 1 (mTORC1) and sterol responsive element binding protein 1 (SREBP1)] in liver than the KO-C group. Long-term DHA intervention attenuates telomere attrition and promotes lipid synthesis via the tuberous sclerosis complex 2 (TSC2)-mTORC1-SREBP1 pathway in KO male mice.