Maternal environmental enrichment affects the corpora lutea and progesterone levels in pregnant mice.

Abstract

Introduction: Maternal lifestyle impacts reproductive performance. Previously, we demonstrated that maternal environmental enrichment promotes pregnancy success in BALB/c mice. As progesterone regulates gestation, we decided to study the effect of maternal environmental enrichment on ovarian physiology during early gestation.

Methods: For this, six-week-old female mice were housed in enriched or control cages for six weeks and then mated with control fertile males. Females with a mucus plug were returned to their respective control or enriched cages. Pregnant mice were euthanized on day 7 of pregnancy, and ovaries and progesterone levels were investigated.

Results: Hematoxylin and eosin slices showed no differences in the area (μm²) of the ovaries between control and enriched females. Also, the number of primordial, primary, preantral, antral, and atretic follicles was similar for both treatments. However, the number and area (μm²) of corpora lutea were increased in the ovaries from the enriched group. Moreover, enriched females presented higher progesterone serum levels and increased 3β-HSD expression.

Discussion: Therefore, maternal environmental enrichment regulates ovarian physiology, and this could promote the benefits previously reported.