Oviductal fluid modulates the dynamics of tyrosine phosphorylation in cryopreserved boar spermatozoa during capacitation

Abstract

Following insemination, spermatozoa are retained in the utero-tubal junction and isthmic region of the oviduct, where essential steps of capacitation are coordinated. Although a majority of the spermatozoa is exposed to similar conditions in the oviduct, the speed of the response varies depending on the individual male and the state of the spermatozoa. The present study evaluated individual boar variations in terms of the ability of spermatozoa to undergo tyrosine phosphorylation in response to isthmic oviductal fluid (ODF). Cryopreserved spermatozoa from four boars were incubated with pre- and post-ovulatory ODF for 6 hr. Sperm kinematics, global protein tyrosine phosphorylation, and dynamics of different phosphorylation patterns were analyzed at hourly interval. The percentage of phosphorylated spermatozoa in the pre-ovulatory ODF-treated group was significantly (P < 0.001) higher than in the other treatment groups. Motility, velocity, and protein tyrosine phosphorylation in spermatozoa in response to ODF and control media also showed differences between boars. Spermatozoa from all four boars showed strong expression of a 19-kDa phosphoprotein while spermatozoa from two boars showed additionally strong expression of a 32-kDa phosphoprotein when incubated with pre-ovulatory ODF. While phosphorylation of proteins in the acrosome and the equatorial segment of the sperm were noticed at an early stage during incubation with ODF, tail phosphorylation appeared at a later stage of capacitation. The results indicate individual variation between boars in terms of sperm proteins, including different phosphorylation patterns, in response to ODF, which might be related to fertility.

Timing of oviductal fluid collection, steroid concentrations, and sperm preservation method affect porcine in vitro fertilization efficiency

“…It might be thought that a more proteolysis-resistant ZP would be harder for frozen-thawed spermatozoa to cross, which, in theory, might have poorer motility and physical strength. However, it is also known that cryopreservation produces a series of changes in the sperm membranes leading to a capacitation-like status and that OF components protect these cryopreserved sperm cells, support their viability and motility, and enhance protein phosphorylation (42)(43)(44). Previous studies have already shown that the percentage of phosphorylation in cryopreserved boar spermatozoa was greater when they were treated with preovulatory OF (43), an effect that would be in agreement with a higher fertilization ability, as seen in the present study.…”

“…However, it is also known that cryopreservation produces a series of changes in the sperm membranes leading to a capacitation-like status and that OF components protect these cryopreserved sperm cells, support their viability and motility, and enhance protein phosphorylation (42)(43)(44). Previous studies have already shown that the percentage of phosphorylation in cryopreserved boar spermatozoa was greater when they were treated with preovulatory OF (43), an effect that would be in agreement with a higher fertilization ability, as seen in the present study. The higher level of penetration and polyspermy with frozen-thawed spermatozoa compared with the fresh samples of the same boar, in the presence of the same batch of preovulatory OF, lead us to conclude that the use of this type of OF would be beneficial for increasing the IVF efficiency with low-quality (fresh or frozen-thawed) semen samples, as is the case in many couples attending infertility clinics.…”

Oviductal secretion and gamete interaction

“…Another study showed that the exposure of boar sperm to porcine oviductal fluid collected in the follicular phase of the estrous cycle promoted boar sperm viability and acrosomal integrity . A recent study has reported that incubation of boar sperm in the presence of pre-ovulatory oviductal fluid caused a significant increase in sperm protein tyrosine phosphorylation compared with incubation with postovulatory oviductal fluid or the control medium (Kumaresan et al 2012). In addition, the observed phosphorylation patterns appeared to be individual dependent in porcine species.…”

“…In some studies, the oviductal fluid was collected by placing a cannula in the oviduct (Leese 1988, Kavanaugh et al 1992, Grippo et al 1995, Way et al 1997, Kumaresan et al 2012.…”

Computer assisted sperm analysis: Relationship between the movement characteristics of buffalo spermatozoa and sire fertility

“…In spite of several developments in the semen cryopreservation, approximately 50% of spermatozoa are rendered immotile by cryopreservation and fertilizing capacity of spermatozoa is significantly decreased (Watson, 2000). Further, individual variations among males in respect to cryotolerance of spermatozoa and fertility has been reported recently (Harayama et al, 2010;Kumaresan et al, 2012) indicating that precise determination of the quality of spermatozoa important for achieving higher conception rates, especially in buffaloes, since buffalo spermatozoa have less cryotolerance capacity compared to cattle spermatozoa and are highly susceptible to hazards during the process of cryopreservation (Andrabi, 2009). …”