Cell surface characteristics of blastocysts from spontaneously ovulating and gonadotropin-treated mice

Area of Science:

• Reproductive Biology
• Developmental Biology
• Mammalian Embryology

Background:

• Hormonal stimulation, particularly with gonadotropins, is widely used in assisted reproductive technologies.
• The surface morphology of mammalian blastocysts is crucial for implantation and development.
• Strain-specific differences in reproductive physiology are well-documented in laboratory mice.

Purpose of the Study:

• To investigate the impact of gonadotropin treatment on the surface architecture of mouse blastocysts.
• To compare blastocyst surface morphology between spontaneously ovulating and gonadotropin-stimulated mice.
• To assess potential differences in response based on female maturity (immature vs. mature).

Main Methods:

• Scanning electron microscopy was employed to visualize and analyze the surface of mouse blastocysts.
• Blastocysts were obtained from two common mouse strains (BALB/cBy and C57BL/6J).
• Females were categorized into spontaneously ovulating or gonadotropin-treated groups, with further subdivision by age (immature and mature).

Main Results:

• Gonadotropin-treated females exhibited blastocysts with significantly fewer microvilli compared to spontaneously ovulating females.
• A greater proportion of smooth surface area was observed on blastocysts from gonadotropin-treated mice.
• The observed alterations in surface architecture were more pronounced in gonadotropin-treated immature females than in similarly treated mature females.

Conclusions:

• Gonadotropin administration alters the surface ultrastructure of mouse blastocysts, characterized by a reduction in microvilli.
• Immature female mice show a more significant response to gonadotropin treatment regarding blastocyst surface morphology.
• These findings highlight the influence of hormonal milieu and female age on early embryonic development and surface characteristics.