Sperm selection in the female mammalian reproductive tract. Focus on the oviduct: Hypotheses, mechanisms, and new opportunities

Holt, William V.; Fazeli, Alireza

doi:10.1016/j.theriogenology.2015.07.019

Cited by 70 publications

(68 citation statements)

References 117 publications

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“…Therefore, the in vitro penetration of oocytes is more a matter of coincidence than a competition and selection process that occurs in vivo 33. In IVF systems, each oocyte has contact with many spermatozoa at the same time.…”

Section: Discussionmentioning

confidence: 99%

Improving porcine in vitro fertilization output by simulating the oviductal environment

Soriano‐Úbeda

García–Vázquez

Romero-Aguirregomezcorta

et al. 2017

Sci Rep

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Differences between the in vitro and in vivo environment in which fertilization occurs seem to play a key role in the low efficiency of porcine in vitro fertilization (IVF). This work proposes an IVF system based on the in vivo oviductal periovulatory environment. The combined use of an IVF medium at the pH found in the oviduct in the periovulatory stage (pHe 8.0), a mixture of oviductal components (cumulus-oocyte complex secretions, follicular fluid and oviductal periovulatory fluid, OFCM) and a device that interposes a physical barrier between gametes (an inverted screw cap of a Falcon tube, S) was compared with the classical system at pHe 7.4, in a 4-well multidish (W) lacking oviduct biological components. The results showed that the new IVF system reduced polyspermy and increased the final efficiency by more than 48%. This higher efficiency seems to be a direct consequence of a reduced sperm motility and lower capacitating status and it could be related to the action of OFCM components over gametes and to the increase in the sperm intracellular pH (pHi) caused by the higher pHe used. In conclusion, a medium at pH 8.0 supplemented with OFCM reduces polyspermy and improves porcine IVF output.

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Section: Discussionmentioning

confidence: 99%

Improving porcine in vitro fertilization output by simulating the oviductal environment

Soriano‐Úbeda

García–Vázquez

Romero-Aguirregomezcorta

et al. 2017

Sci Rep

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“…Spermatozoa selected by means of the SUT can also behave differently in the cervix and oviduct secretions of the female reproductive tract, which may cause an impaired ability to travel to the site of fertilization. The female reproductive tract has developed several mechanisms to select only the most viable spermatozoa to participate in fertilization (Holt & Fazeli, 2016).…”

Section: Resultsmentioning

confidence: 99%

A novel flush technique to simulate natural dispersal of spermatozoa in the female reproductive tract and expedite motility assessment of fresh ejaculated Merino (<i>Ovis aries</i>) sperm

Boshoff¹,

Lambrechts²,

Maree³

et al. 2018

SA J. An. Sci.

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Motility is an important criterion in the assessment and quantification of the quality of ejaculated and epididymal sperm samples. Ovine sperm spermatozoa are particularly susceptible to cryodamage, and shortening the interval from collection to cryostorage may potentially minimize the negative effects of cryopreservation, thereby improving the post-thaw viability of ram spermatozoa. The use of the swim-up technique (SUT) in quantifying spermatozoa motility is well documented, especially for the isolation of highly motile spermatozoa for assisted reproductive purposes. However, this technique is time consuming and involves a swim-up period of 10 minutes before the motility of a sample is recorded by using computerassisted sperm analysis (CASA) software such as the Sperm Class Analyser® (SCA®). The novel flush technique (FT) allows for capturing of sperm motility tracks via the SCA® system shortly after semen collection, that is, within a minute. This study compared fresh ejaculated sperm motility traits by using the SUT and FT. Motility evaluations were performed using 45 semen samples obtained from 15 adult Merino rams (Ovis aries) at weekly intervals. Motility recordings were captured at 100 frames per second, using a calibrated 20 µm deep Leja slide. The percentage total motile spermatozoa of samples subjected to the FT was 89.2%, which was significantly higher than that recorded by the SUT (83.9%). The results also indicated that the wobble (WOB) parameter showed significantly higher values when using the FT, and parameters curvilinear velocity (VCL) and amplitude of the lateral head displacement (ALH) indicated significantly higher values when using the SUT. Establishing the ideal spermatozoa concentration and analysis of sperm subpopulation motility characteristics would assist in the optimization of the FT, and its use in CASA motility analysis of ovine spermatozoa. Standardization of CASA analysis of ovine semen samples, which would enable the selection of quality spermatozoa samples for use in field insemination (fresh samples) or in vitro fertilization programs, and laparoscopic AI cryopreserved samples warrants further investigation.

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“…As polyspermy is invariably lethal, selection will favor the evolution of mechanisms that function to prevent it . A stringent filtering/selection process that results in only the very best sperm entering the oviduct would certainly achieve this . Females would further benefit if egg mechanisms enabled CFC over fertilizing sperm …”

Section: Conflict Between the Gametes: Aggressive Sperm And Defensivementioning

confidence: 99%

Postmating sexual conflict and female control over fertilization during gamete interaction

Firman

2018

Annals of the New York Academy of Sciences

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Males and females rarely have identical evolutionary interests over reproduction, and when the fitness of both sexes is dependent upon paternity outcomes, sexual conflict over fertilization is inevitable. In internal fertilizers, the female tract is a formidable selective force on the number and integrity of sperm that reach the egg. Selection on sperm quality is intensified when females mate multiply and rival males are forced to compete for fertilizations. While male adaptations to sperm competition have been well documented (e.g., increased sperm fertilizing capacity), much less attention has been given to the evolutionary consequences of postmating sexual conflict for egg form and function. Specifically, increased sperm competitiveness can be detrimental by giving rise to an elevation in reproductive failure resulting from polyspermy. Spanning literature on both internal and external fertilizers, in this review I discuss how females respond to sperm competition via fertilization barriers that mediate sperm entry. These findings, which align directly with sexual conflict theory, indicate that females have greater control over fertilization than has previously been appreciated. I then consider the implications of gametic sexual conflict in relation to the development of reproductive isolation and speculate on potential mechanisms accounting for "egg defensiveness." Finally, I discuss the functional significance of egg defensiveness for both the sexes, and sperm selection for females.

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Sperm selection in the female mammalian reproductive tract. Focus on the oviduct: Hypotheses, mechanisms, and new opportunities

Cited by 70 publications

References 117 publications

Improving porcine in vitro fertilization output by simulating the oviductal environment

Improving porcine in vitro fertilization output by simulating the oviductal environment

A novel flush technique to simulate natural dispersal of spermatozoa in the female reproductive tract and expedite motility assessment of fresh ejaculated Merino (<i>Ovis aries</i>) sperm

Postmating sexual conflict and female control over fertilization during gamete interaction

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