CALCIUM IONOPHORE A23187 EFFECT ON ACQUISITION OF FERTILIZING ABILITY IN EQUINE CRYOPRESERVED SPERMATOZOA

LAIZ-QUIROGA, LUCIA; NAVARRO MICAELA; MARTÍNEZ LEÓN, EDUARDO ANTONIO; BUFFONE, MARIANO G.; MUTTO ADRIAN ANGEL; OSYCKA SALUT CLAUDIA ELENA

BUENOS AIRES

Jornada; XXIV JORNADAS ANUALES DE LA SOCIEDAD ARGENTINA DE BIOLOGIA; 2022

Spermatozoa must undergo three events to fertilize an oocyte in vivo: capacitation, hyperactivation and acrosome reaction. Therefore, it is necessary to induce these physiological events in vitro in the masculine gamete during assisted reproductive techniques. Even though the in vitro conditions under which many species acquire their fertilizing ability are well known, to this day, there is no standard protocol to induce these events in equine cryopreserved spermatozoa. Thus, there is no available protocol for embryo production through in vitro fertilization (IVF) with these samples. It has been proven that brief exposure of murine and bovine spermatozoa to calcium ionophore A23187 and the consequent calcium influx to the cell cytoplasm increases their fertilizing ability in vitro and embryo production due to the induction of capacitation and hyperactivation. Moreover, A23187 increases events related to capacitation without inducing the classical capacitation signaling pathway such as PKA-activation (pPKA) or protein tyrosine phosphorylation (pTyr). Given the current difficulties in equine embryo production through IVF with cryopreserved spermatozoa and the previously shown effects of the calcium ionophore in spermatozoa from other species, this work aimed to study the potential fertilizing ability of equine cryopreserved spermatozoa that were previously exposed to A23187.First, we studied the effect of A23187 (1 µM) on spermatozoa. After 10 minutes of exposure, the ionophore decreased the spermatozoa motility (CASA, p0,05) or acrosome status (PSA-FITC, IF, p>0,05). After removing the ionophore, the spermatozoa were incubated under non-capacitating conditions for 20 minutes and motility was reassessed, and their fertilizing ability was studied. The previous incubation with A23187 increased the hyperactivated sperm population (CASA, p