Influence of complement depletion on sperm function in the female rabbit

Area of Science:

• Reproductive immunology
• Mammalian fertilization

Background:

• The complement system plays a role in immune responses.
• Its specific role in sperm-egg interactions during fertilization is not fully understood.

Purpose of the Study:

• To investigate the role of complement in sperm transport and fertilization in rabbits.
• To determine if complement activation is necessary for the acrosome reaction.

Main Methods:

• Female rabbits were treated with cobra venom factor (CVF) to deplete complement.
• Mating was performed, and eggs were collected post-coitum.
• Sperm penetration of eggs and presence in reproductive tract flushings were assessed.

Main Results:

• Complement depletion did not inhibit the acrosome reaction.
• Significantly more spermatozoa penetrated egg vestments in CVF-treated rabbits.
• Increased sperm numbers were found in the oviducts and uterus of CVF-treated females.

Conclusions:

• Complement activation is not essential for the acrosome reaction in rabbits.
• Complement-dependent factors may limit sperm migration within the female reproductive tract after insemination.