Ultrastructural analysis of artificially activated rabbit eggs

Area of Science:

• Reproductive Biology
• Developmental Biology
• Cell Biology

Background:

• Understanding artificial egg activation is crucial for reproductive technologies.
• Parthenogenetic activation mimics natural fertilization processes.
• Rabbit egg activation provides a model for studying early embryogenesis.

Purpose of the Study:

• To investigate the ultrastructural events during artificial activation of rabbit eggs.
• To compare artificial activation processes with natural fertilization and embryogenesis.
• To elucidate the role of cold treatment in initiating egg activation.

Main Methods:

• Rabbit eggs were artificially activated by cold shock (10°C for 24 hours) followed by incubation at 37°C.
• Ultrastructural investigations using electron microscopy were performed on activated eggs.
• Ova were examined at various time points (2 to 24 hours) post-incubation.

Main Results:

• Cold treatment induced chromosome aggregation and reticulum formation, with reduced meiotic spindle microtubules.
• Activated eggs formed a central nucleus capable of cleavage, with approximately 95% activation at 12 hours at 37°C.
• Artificial activation did not involve second polar body formation or cortical granule release, unlike natural fertilization.

Conclusions:

• Cold-induced artificial activation of rabbit eggs initiates key early developmental events.
• The process shares similarities with fertilization but lacks specific maternal responses.
• Prolonged incubation of artificially activated eggs leads to abnormal development and fragmentation.