Assessment of Sperm Binding Capacity in the Reservoir Using an In Vitro Model of Oviduct Epithelial Spheroids in...

The sperm reservoir in the isthmus, the distal part of the oviduct, plays important roles in sperm survival and acquisition of sperm fertilization competence. Here, we describe an in vitro model of bovine oviduct spheroids, easy to culture and normalize, and allowing robust quantification by confocal microscopy of sperm binding capacity to isthmic epithelial cells. This assay may be used to compare sperm binding capacity between males and ejaculates, evaluate sperm membrane integrity and correlation with male fertility, and conduct studies on sperm-oviduct interactions. The method may be implemented in other species.