Javiera Navarrete & Bélgica Vásquez

Early-life stress and obesity represent critical public health challenges. This study investigated the effects of maternal separation (MS), as a model of early-life adversity, and post-weaning high-fat diet (HFD) exposure on plasma lipid profile and visceral adipose tissue organization in C57BL/6 male mice. Mice underwent MS during the early postnatal period or were left unmanipulated (UM). Following weaning, animals were allocated to a control diet (CD) or an HFD, yielding four experimental groups (n = 5 per group): UM-CD, MS-CD, UM-HFD, and MS-HFD. Plasma lipid profile, global adiposity index, and the mass of perigonadal (PGAT), retroperitoneal (RPAT), and mesenteric (MSAT) visceral adipose tissue deposits, as well the histological architecture and sectional area (SA) of adipocytes, were evaluated using morphological and quantitative analyses. HFD was the primary determinant of alterations in the plasma lipid profile, particularly total cholesterol (CHOL-T) and low-density lipoprotein cholesterol (LDL-C), whereas MS selectively modulated the magnitude of these changes. The global adipocity index was predominantly influenced by dietary intervention, with no significant effect of MS. In contrast, visceral fat pad expansion was heterogeneous and depot-specific, with a significant diet × MS interaction detected in RPAT and, to a lesser extent, in MSAT. Histological and quantitative analyses showed that HFD induced a significant increase in SA in all three visceral fat pads, with MS contributing in a depot-dependent manner, revealing non-uniform patterns of adipose tissue expansion. In conclusion, these findings indicate that MS does not act as a direct determinant of obesity, but rather as a programming factor that modulates the plasma lipid profile and the structural response of visceral adipose tissue to an obesogenic nutritional environment in adulthood.

KEY WORDS: Maternal separation; High-fat diet; Lipid profile; Visceral adipose tissue; Mouse.

NAVARRETE, J. & VÁSQUEZ, B. Effects of maternal separation on lipid homeostasis and visceral adipose tissue organization in mice fed a high-fat diet post-weaning. Int. J. Morphol., 44(1):9-22, 2026.