Ability of the zebra sperm to induce pig and horse oocyte activation and in vitro preimplantation embryo development after ICS

GAMBINI, A.; FLORES BRAGULAT, A.; SALAMONE, DF.; DUQUE RODRIGUEZ, M.; DEMERGASI, N.; BRISKI, O.; LOSSINO, L.

JOURNAL OF EQUINE VETERINARY SCIENCE

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2020 vol. 89

0737-0806

Several equids have gone extinct and many extant equids arecurrently considered vulnerable to critically endangered. In vitroembryo production has been promoted over the last years for theirpotential of genetic rescue and preservation. This work aimed: 1) tocompare the ability of the zebra, equine, and pig sperm to inducepronuclear formation and to recruit maternal SMARCA4 wheninjected into matured pig oocytes and 2) to evaluate whether domestic horse oocytes support preimplantation development afterinjection of zebra sperm. Oocyte collection, ICSI, culture and blastocyst fixation were performed as described by Rodriguez et al.Reproduction, Fertility and Development, 2019; 31:1805?1811.Frozen epididymal sperm cells from a dead zebra were used.Refrigerated and frozen ejaculated semen were used for pig andhorse groups respectively. Blastocyst quality was assessed throughimmunofluorescence, determining total cell number and the number of nuclei positive to YAP1 and SOX2. Significantly more pig oocytes were not activated after injection with zebra sperm comparedto the horse and pig sperm (Table 1), although SMARCA4 pronuclearintensity levels were similar among groups. Significant lowercleavage rates were observed in zebroid embryos, although blastocyst rate was similar between groups (Table 2). No significant differences were found in total cell number between groups. Horse andzebroid blastocysts showed a similar expression pattern of SOX2 andnuclear YAP1. The majority of the nuclei were positive for YAP1, andmost SOX2+ nuclei were clustered and negative for YAP1. Weshowed that SMARCA4 recuritment in the male pronuclei is independent of the genetic background of the sperm and we demonstrated that domestic horse oocyte support reprogramming of zebrasperm and the subsequent preimplantation development withoutcompromising blastocyst cell number neither the expression ofSOX2/YAP1. Our results encourage the use of domestic horse oocytesas a model to study in vitro zebra embryos on behalf of preservationof valuable genetic in conservation programs for endangered orextinct equid species.