Restoration of Motility in Acrosome‐Reacted Boar Spermatozoa Induced by the Ionophore 4‐Br‐
A23187
David Martín‐Hidalgo, Violeta Calle‐Guisado, Beatriz Macías‐García, Lauro González‐Fernández ABSTRACT
The acrosome reaction (AR) is a calcium‐dependent exocytotic event required for successful fertilization. Calcium ionophores are commonly used to induce AR in vitro; however, this treatment is associated with a significant loss of sperm motility. The aim of this study was to evaluate the recovery of motility in boar spermatozoa after ionophore‐induced AR and to assess the role of extracellular calcium. Boar spermatozoa were incubated with 10 μM 4‐Br‐A23187 to induce AR. Then, spermatozoa were washed and incubated for 30 min in a recovery medium containing either 1 mM calcium or 5 mM EGTA. The AR was analysed by flow cytometry, and motility parameters were assessed using a CASA system. Ionophore treatment induced AR and caused a marked reduction in sperm motility, which was partially recovered in the presence of 5 mM EGTA, but not in the presence of 1 mM calcium. These results suggest that extracellular calcium inhibits the restoration of motility after ionophore‐induced AR in boar spermatozoa.