Effects of complement component 3 derivatives on pig oocyte maturation, fertilization and early embryo development in vitro.

Complement component 3 (C3) has well-established roles within immune system, but its roles outside of immune system are less characterized. The extensive presence of C3 throughout the female reproductive tract, and its temporal, and gamete-specific regulation of expression suggest a potential role for C3 in reproduction. In the present investigation, the effects of C3, C3b and iC3b on porcine oocyte maturation, fertilization and embryonic development were examined. We identified the ability of iC3b to positively influence oocyte maturation. No effects on fertilization efficiency, penetration rates, polyspermy and blastocyst formation were observed. However, C3, C3b and iC3b presence in embryo culture medium resulted in fewer total cells in test blastocysts compared to control blastocysts. The results of this study indicate a potential function for iC3b in oocyte maturation. Furthermore, it was demonstrated that the presence of either C3, C3b or iC3b has a negative influence on early embryonic development in the porcine species.