http://directory.umm.ac.id/Data%20Elmu/jurnal/A/Animal%20Reproduction%20Science/Vol60-61.Issue1-4.Jul2000/1971.pdf

The causes of reduced fertility with cryopreserved semen

At coitus, human sperm are deposited into the anterior vagina, where, to avoid vaginal acid and immune responses, they quickly contact cervical mucus and enter the cervix. Cervical mucus filters out sperm with poor morphology and motility and as such only a minority of ejaculated sperm actually enter the cervix. In the uterus, muscular contractions may enhance passage of sperm through the uterine cavity. A few thousand sperm swim through the uterotubal junctions to reach the Fallopian tubes (uterine tubes, oviducts) where sperm are stored in a reservoir, or at least maintained in a fertile state, by interacting with endosalpingeal (oviductal) epithelium. As the time of ovulation approaches, sperm become capacitated and hyperactivated, which enables them to proceed towards the tubal ampulla. Sperm may be guided to the oocyte by a combination of thermotaxis and chemotaxis. Motility hyperactivation assists sperm in penetrating mucus in the tubes and the cumulus oophorus and zona pellucida of the oocyte, so that they may finally fuse with the oocyte plasma membrane. Knowledge of the biology of sperm transport can inspire improvements in artificial insemination, IVF, the diagnosis of infertility and the development of contraceptives.

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Sperm transport in the female reproductive tract

http://directory.umm.ac.id/Data%20Elmu/jurnal/A/Animal%20Reproduction%20Science/Vol62.Issue1-3.Aug2000/2030.pdf

Storage of boar semen.

In mammals, insemination results in the transmission of seminal factors that act, in the female reproductive tract, to promote sperm survival, to “condition” the female immune response to tolerate the conceptus and to organise molecular and cellular changes in the endometrium to facilitate embryo development and implantation. These events are initiated when signalling agents, including transforming growth factor-β and other cytokines and prostaglandins secreted by seminal vesicle and prostate glands, interact with epithelial cells in the cervix and uterus to activate cytokine synthesis and to induce cellular and molecular changes resembling a classical inflammatory cascade. The consequences are the recruitment and activation of macrophages, granulocytes and dendritic cells, which have immune-regulatory and tissue-remodelling roles that culminate in improved endometrial receptivity to the implanting embryo. Cytokines elicited by seminal activation have embryotrophic properties and also contribute directly to the optimal development of the early embryo. This review summarises our current understanding of the physiology of responses to seminal plasma in the female reproductive tract and considers the evolutionary significance of seminal plasma in influencing female tissues to promote the success of pregnancy.

Seminal plasma and male factor signalling in the female reproductive tract

Computer-assisted sperm analysis (CASA): capabilities and potential developments.

Effect of time of insemination relative to ovulation on fertility with liquid and frozen boar semen.

Fertilization success cannot be attributed solely to the absolute number of vital, motile, morphologically normal spermatozoa inseminated into the female but more especially to their functional competence. A range of in vitro tests has therefore been developed to monitor crucial aspects of sperm function: their ability to adapt to changing osmotic conditions, to bind to the oviductal epithelium, and to undergo capacitation in an appropriate and timely manner. The tests employ flow cytometry in conjunction with fluorescent techniques, electronic cell counting, and computer-assisted image area analysis. The highly quantitative analysis provided by electronic sizing and flow cytometry enables assessment of representative cell numbers in a very short time with high reproducibility. More importantly, it allows the detection of physiological heterogeneity within an ejaculate in terms of the development of cell subpopulations and enables the kinetic analysis of changes in living cell suspensions. The tests offer a promising strategy for evaluating fertility in domestic animals. The capability for volume regulation ensures that sperm recover from the tonic shocks experienced at ejaculation and during cryopreservation. Assessment of capacitation in vitro provides valuable information on both the sperm's ability to respond to fertilizing conditions and the sequence and rates of ongoing capacitation/destabilization processes. The monitoring of response to capacitating conditions in kinetic terms allows the sensitive and adequate detection of sperm populations expressing fertilization attributes and their ability to respond to external stimuli in a timely manner. However, subfertility is likely to be associated with a suboptimal response (i.e. too high or too low) rather than a minimal response.

/pdf/determinants-of-sperm-quality-and-fertility-in-domestic-2f39kzkh4r.pdf

Determinants of sperm quality and fertility in domestic species

was used as the parameter of binding capacity. Binding of spermatozoa to oviductal epithelial explants was dependent in a linear manner on the number of spermatozoa added (P < 0.05). No difference was found in initial sperm binding between isthmic and ampullar explants. There was no effect of the stage of the oestrous cycle or the reproductive status of the female donor. There was a significant effect (P < 0.05) of the individual boar on the binding index. The binding index correlated negatively with the percentage of spermatozoa with cytoplasmic droplets and the percentage of morphologically abnormal spermatozoa (P < 0.05). Epididymal spermatozoa showed significantly lower initial binding capability than did ejaculated spermatozoa from the same boars (P < 0.05); therefore, components of seminal plasma may play a role in the binding process. The individual differences revealed by this study and their relation to morphology and contact of spermatozoa with seminal fluid indicate a selective function of sperm‐oviduct binding.

/pdf/selective-sperm-binding-to-pig-oviductal-epithelium-in-vitro-41y4tc43h1.pdf

Selective sperm binding to pig oviductal epithelium in vitro.

Sperm are stored in the isthmic region of the oviduct under conditions that maintain sperm viability and suppress motility. This region is also the site in which essential steps of the capacitation process are coordinated with the appearance of the ovulated egg. The influx of Ca2+ and phosphorylation of sperm proteins are features of the ongoing capacitation process. Using a cell-culture system of oviductal epithelial cells, it was found that sperm bound to the epithelial cells showed a reduced Ca2+ uptake and almost no tyrosine phosphorylation as shown by indirect immunofluorescence. Furthermore, sperm viability, measured as membrane integrity with propidium iodide, is significantly prolonged as compared to sperm in suspension. The formation of the sperm reservoir appears to be mediated by carbohydrate-protein interaction. In the pig, it has been found that mannosyl-oligosaccharides exposed by the epithelial cells are high-affinity ligands for sperm-associated lectins. Ovalbumin and mannopentaose are effective inhibitors of sperm binding to explants of oviductal epithelium. Spermadhesins, a new class of animal lectins and the major secretory products of the porcine seminal vesicle, associate with the sperm surface at ejaculation and are candidate molecules for the receptors of the epithelial carbohydrates. J. Exp. Zool. 292:210–215, 2002. © 2002 Wiley-Liss, Inc.

Dagmar Waberski

Papers

Computer-assisted sperm analysis (CASA): capabilities and potential developments.

Effect of time of insemination relative to ovulation on fertility with liquid and frozen boar semen.

Determinants of sperm quality and fertility in domestic species

Selective sperm binding to pig oviductal epithelium in vitro.

Function of the mammalian oviductal sperm reservoir.