Table 2.
Evidence of sperm selection by binding to OECs
| Parameter | Species | Oviduct Model | Results | References |
|---|---|---|---|---|
| DNA Damage | Bull | OEC aggregates | Sperm-binding index from frozen–thawed samples is negatively correlated to sperm DNA fragmentation index (sperm chromatin structure assay). | [103] |
| Man | Bovine OEC monolayer | Bound sperm have lower abnormal chromatin and mean ratio of denatured DNA (sperm chromatin structure assay) compared with free sperm. | [102] | |
| Capacitation | Boar | OEC monolayer and ex vivo oviduct explant | Bound sperm show lower levels of tyrosine phosphorylation and different phosphotyrosine distribution patterns (immunofluorescence) compared with free sperm. | [101] |
| Boar | OEC suspension | A higher proportion of bound sperm are uncapacitated (fluorescent antibiotic chlortetracycline staining) compared with control samples. | [100] | |
| Boar | OEC monolayer | Free sperm have higher levels of tyrosine phosphorylation (immunofluorescence) and higher rates of phosphatidylserine translocation (Annexin V-Cy3™ Apoptosis Detection Kit) compared with bound and unselected sperm. | [64] | |
| Boar | OEC monolayer | Bound sperm show lower cytosolic calcium concentration (fluo-3-AM staining) and tyrosine phosphorylation of membrane proteins (distribution of Cy-3 staining), and higher membrane integrity (propidium iodide) and motility, compared with free sperm. | [93] | |
| Fertilization Competence | Bull | OEC monolayer | Bound sperm, collected after heparin-induced release, show higher ZP binding and cleavage rate after IVF, compared with free sperm and sperm cultured with a porous insert that prevented direct contact with OECs. | [65] |
| Bull | OEC suspension | Free sperm show lower fertilization rate after IVF and mean number of sperm bound to the ZP than control sperm. Free sperm have lower membrane integrity (hypo-osmotic-swelling-test). | [104] | |
| Bull | OEC monolayer | Bound sperm, collected after progesterone-induced release, produce higher cleavage and blastocyst rates after IVF, compared with control sperm. | [66] | |
| Boar | OEC monolayer | Free sperm produce lower penetration and fertilization rates compared with bound and control sperm. | [64] |
Binding Index = sperm bound per unit area of oviduct explant, OEC monolayers, or OEC aggregates. Control = sperm that was not cultured with OECs.