Characteristics of sperm binding to the mouse oviduct

Abstract

A wide variety of animals store sperm between mating and ovulation. The sperm reservoir prolongs sperm lifespan and keeps sperm in a quiescent stage due to delayed capacitation and suppressed motility. The objective of this study was to determine different characteristics of sperm binding to the oviduct. The study was conducted using the translucent mouse oviduct ex vivo. The specificity of sperm binding was determined using the isthmus, ampulla, and trachea (n = 4). The results showed no difference in binding between isthmus and trachea (P > 0.05) but binding to the ampulla was less than the isthmus (P < 0.05). Capacitation status also affected sperm binding (n = 3). The number of sperm from non-capacitated samples bound to the isthmus was significantly higher than the number of bound capacitated sperm (P < 0.05). Despite increased stiffness of oviduct cilia as female age, the number of sperm bound to the isthmus of older females was higher than younger females (P < 0.05). The number of bound sperm was different throughout estrous stages (P < 0.05) with diestrus being the highest (n = 3). Species-specific binding was also examined by allowing porcine and mouse sperm to bind the mouse isthmus (n =3). A significantly higher number of mouse sperm bound to the mouse isthmus than porcine sperm (P < 0.05). In conclusion, sperm binding to the oviduct ex vivo was not completely specific to oviduct epithelial cells or age-dependent but was species-restricted, capacitation-dependent and dependent on the stage of estrous.