Persistent vaginal cornification in mice treated with estrogen prenatally

Area of Science:

• Endocrinology
• Developmental Biology
• Reproductive Science

Background:

• Estradiol-17beta is a critical hormone in reproductive development.
• Prenatal exposure to endocrine-disrupting chemicals can have long-term effects on reproductive health.

Purpose of the Study:

• To investigate the long-term effects of prenatal estradiol-17beta exposure on the vaginal epithelium and ovarian function in mice.
• To determine if these effects are irreversible and persist into adulthood.

Main Methods:

• ICR strain female mice were administered a single injection of 50 mug estradiol-17beta at different developmental stages: day 17 of fetal life, day 15 of fetal life, day of birth, or 3 days postnatal.
• Vaginal epithelium and ovarian morphology were examined at 3-5 months of age, with ovaries assessed for the presence of corpora lutea.

Main Results:

• Prenatal exposure on day 17 resulted in irreversible vaginal epithelial changes in 12 of 14 mice, persisting post-ovariectomy.
• Exposure on day 15 led to similar vaginal changes in 6 of 12 mice, with only one retaining corpora lutea.
• Postnatal exposure did not induce significant vaginal changes and resulted in ovaries with follicles and hypertrophied interstitial tissue, but no corpora lutea.

Conclusions:

• Prenatal exposure to estradiol-17beta during critical developmental windows can induce permanent alterations in the vaginal epithelium of female mice.
• The timing of prenatal exposure significantly influences the severity and persistence of these effects, as well as ovarian development.
• These findings underscore the sensitivity of the developing reproductive system to hormonal influences during gestation.