Cortical granules reaction after intracytoplasmic sperm injection

Area of Science:

• Reproductive Biology
• Cell Biology
• Developmental Biology

Background:

• The cortical reaction (CR) is a crucial event in mammalian oocytes, typically triggered by sperm-egg fusion.
• Intracytoplasmic sperm injection (ICSI) bypasses natural fertilization, raising questions about CR induction.

Purpose of the Study:

• To investigate the occurrence of the cortical reaction (CR) after ICSI.
• To determine the correlation between CR and the meiotic status of human oocytes following ICSI.

Main Methods:

• Analysis of chromosomal status using Hoechst staining.
• Assessment of CR occurrence and fluorescent patterns via confocal laser scanning microscopy.
• Utilized lectin lens culinaris and Texas Red staining for CR evaluation.

Main Results:

• A positive correlation was observed between oocyte activation and CR occurrence post-ICSI.
• Unfertilized, unactivated oocytes showed no CR.
• Partially activated oocytes exhibited a moderate CR, while fully activated oocytes displayed a strong CR.

Conclusions:

• Oocyte activation is a prerequisite for the cortical reaction (CR) during ICSI, mirroring natural fertilization processes.
• The intensity of the CR correlates with the degree of oocyte activation.