Oocyte activation deficiency: a role for an oocyte contribution?

Area of Science:

• Reproductive Biology
• Developmental Biology
• Genetics

Background:

• Infertility affects 10-16% of couples globally, with male, female, or combined factors contributing.
• Assisted reproductive technologies like IVF and ICSI are common treatments, but fertilization failure can still occur.
• While sperm factors are often implicated, oocyte deficiencies may also play a significant role in unexplained infertility.

Purpose of the Study:

• To review the roles of sperm and oocyte factors in oocyte activation deficiency.
• To emphasize the underappreciated contribution of oocyte factors to fertilization failure.
• To identify potential molecular targets within the oocyte for future diagnostic and therapeutic development.

Main Methods:

• A critical literature review was conducted using PubMed.
• The review focused on studies related to sperm and oocyte factors in oocyte activation deficiency.
• Included were studies on in vitro oocyte maturation in human and animal models.

Main Results:

• Phospholipase C zeta (PLCζ) is identified as a key sperm oocyte activation factor.
• Another sperm protein, post-acrosomal WWP-binding domain protein, may also be significant.
• Defects in the oocyte's molecular machinery interacting with sperm proteins can cause fertilization failure, impacting calcium release crucial for activation.

Conclusions:

• Oocyte activation deficiency results from a combination of sperm and oocyte factors.
• The role of oocyte factors in fertilization failure is significant and warrants further investigation.
• Developing diagnostic assays targeting oocyte molecular machinery could lead to new infertility treatments.