Maternal protein restriction affects fetal ovary development in sheep

Area of Science:

• Reproductive biology
• Developmental programming
• Maternal-fetal medicine

Background:

• Maternal malnutrition during gestation can lead to adverse fetal development.
• Reduced ovarian reserve and fertility in offspring are potential lifelong consequences of poor fetal ovarian development.
• Understanding the impact of maternal nutrition on fetal ovarian development is crucial for offspring reproductive health.

Purpose of the Study:

• To investigate the effects of maternal protein restriction on germ cell and blood vessel development in fetal sheep ovaries.
• To determine if maternal dietary protein levels influence fetal ovarian weight, germ cell parameters, and vascularization.
• To assess the potential for maternal malnutrition to alter the developmental trajectory of the fetal ovary.

Main Methods:

• Ewes were fed control or low-protein diets from conception to day 65 of gestation.
• Fetal ovaries were analyzed using histological and immunohistochemical techniques.
• Quantification of germ cells (OCT4, VASA, DAZL), proliferation (Ki67), apoptosis (caspase 3), and vascularization (CD31) was performed.

Main Results:

• Maternal protein restriction significantly reduced fetal ovary weight (P < 0.05) but did not affect fetal weight (P > 0.05).
• Germ cell density, proliferation, apoptosis indices, and ovarian vascularity were not significantly altered by maternal diet (P > 0.05).
• Specific germ cell markers (OCT4, VASA, DAZL) showed no significant differences in numbers or density within ovigerous cords between dietary groups.

Conclusions:

• Maternal protein restriction in early gestation decreases fetal ovarian weight in sheep.
• Despite reduced ovarian weight, key aspects of germ cell development and ovarian vascularity are maintained.
• These findings suggest that maternal protein restriction may impact ovarian development through mechanisms independent of germ cell proliferation, apoptosis, or vascularization, potentially affecting long-term fertility.