Involvement of peroxiredoxins in mouse oocyte maturation and in vitro embryo development

ADEL R. MOAWAD; MARÍA C. FERNÁNDEZ; CRISTIAN O´FLAHERTY

Encuentro; CHHD annual retreat; 2017

Peroxiredoxins (PRDXs) are highly conserved antioxidant enzymes and are implicated in multiple biologicalprocesses. PRDXs and particularly PRDX6 play a vital role in protecting spermatozoa against oxidative stress.However, little is known about their role on oocyte maturation and embryo development. We elucidatedwhether the lack of PRDX6 or inhibition of PRDXs activities could impair in vivo and in vitro oocyte maturation,meiotic spindle organization and pre-implantation development after IVF in mice. COCs from WTsuperovulated females were matured in vitro in the presence or absence of Conoidin A or MJ33, inhibitors of2-Cys PRDX peroxidase or PRDX6 Ca2+-iPLA2 activities, respectively for 16 h. Maturation rates (determinedby extrusion of PB1), spindle organization (visualized by immunostaining of α-tubulin), and embryodevelopment were analyzed. Ovulation rates and quality of ovulated oocytes were compared between Prdx6-/- and WT females. Ovulation rates and numbers of in vivo matured oocytes were significantly lower in Prdx6-/- females than WT. Maturation, cumulus expansion, normal spindle organization, cleavage and blastocyst development were lower in Prdx6-/- oocytes than WT. MJ33 and Conoidin A (10 or 20 μM) reduced these parameters in WT oocytes. In conclusion, our results indicate that PRDXs particularly PRDX6 are critical antioxidant enzymes in the process of oocyte maturation and embryo development in mice.