Modulation of Sperm Function during Sperm Transport in the Female

In the cow, sow and mare, a functional tubal sperm reservoir is established before ovulation to ensure availability of suitable numbers of viable spermatozoa for fertilization. Although identification of subpopulations reaching this reservoir has been attempted, it is still unclear whether this recruitment is programmed or fortituous. Those spermatozoa not reaching the oviduct are generally destroyed by phagocytosis of invading leukocytes. While the type of ejaculate differs in these species, seminal plasma proteins and/or the spermatozoa appear to act as leukocyte chemoattractant both in vitro and in vivo. Those spermatozoa in the sperm reservoir not only escape phagocytosis or rejection by the female immune system but sustain viability and potential fertilizing capacity by not capacitating or acrosome-reacting while residing in the oviduct. Sperm numbers in the reservoir diminish gradually in relation to ovulation, spermatozoa being continuously redistributed towards the upper isthmus. In vitro, only uncapacitated spermatozoa bind to epithelial explants, suggesting that the reservoir milieu modulates sperm capacitation. In vivo, most viable spermatozoa during preovulatory spontaneous standing oestrus are uncapacitated, with capacitation significantly increasing after ovulation. In either species, there seems to be different components of the oviductal fluid effecting capacitation, and bicarbonate appears to be common denominator for the membrane destabilizing changes that encompasses the first stages of the process. Such effects can be blocked or even reversed by co-incubation with isthmic fluid or specific glycosaminoglycans such as hyaluronan. Although the pattern of response to in vitro induction of sperm capacitation is similar for all spermatozoa, the capacity of response and its speed is very individual. Such diverse individual response to capacitation would not only confirm capacitation does not occur massively in the reservoir but clearly insures full sperm viability before ovulation and the presence of spermatozoa at different stages of capacitation in the upper oviduct, thus maximizing the chances of normal fertilization

Ocjena ejakulata: može li se procijeniti plodnost?

This review critically comments on established and emerging methods of semen evaluation that would foresee the fertility of the ejaculate (neat or processed) or the male. Functional sperm testing through biomimetic in vitro assays are priority since these, by resembling events during sperm transport, storage and interaction with the female genital tract and the oocyte, best provide clues for sperm selection and the role of sperm sub-populations in the ejaculate. The review also focuses on the exploration of the genome, the transcriptome and the proteome of both spermatozoa and the seminal plasma which may help to unveil how spermatozoa and seminal plasma components would signal to the female and link to fertility and even prolificacy. Specific seminal plasma components, both among individuals and portions of the ejaculate, not only relate to sperm survival but also to signal the female immune system towards a differential immune tolerance warranting fertility.Ovaj pregledni članak pruža kritički osvrt na standardne i inovativne metode za procjenu kakvoće sjemena kako bi se predvidio oplodni potencijal ejakulata (nativnog ili obrađenog) i mužjaka. Funkcionalna testiranja spermija u in vitro uvjetima su nužna, budući da se slični procesi odvijaju tijekom transporta spermija, pohrane i interakcije sa ženskim spolnim sustavom i oocitama, jer pružaju uvid u ulogu pojedinih subpopulacija spermija u ejakulatu i time pomažu kod odabira spermija. Nadalje, ovaj se članak isto tako usredotočuje na istraživanje genoma, transkriptoma i proteoma spermija i sjemene plazme što može pomoći pri otkrivanju kako spermiji i molekule sjemene plazme mogu dati signal ženki i povezati to s plodnošću pa čak i s brojem potomaka. Specifične molekule sjemene plazme koje se razlikuju između jedinki između pojedinih frakcija ejakulata, povezane su s preživljavanjem spermija kao i s majčinom imunosnom tolerancijom prema spermijima što omogućuje plodnosti

Advances in Boar Semen Cryopreservation

The present paper highlights aspects of the cryopreservation of boar semen, a species with particular large, fractionated ejaculates, and a cumbersome cryotechnology that had prevented its commercial application. With the dramatic increase of use of liquid pig semen for artificial breeding over the past decade, developments on cryopreservation alongside the routine use of stud boar semen for AI had been promoted. Recent advances in our laboratory, accommodating the best use of portions of the sperm-rich fraction of the ejaculate for cryopreservation of the sperm-peak portion (P1) and parallel use of the rest of the collected ejaculated spermatozoa, appears as a suitable commercial alternative

Ocjena ejakulata: može li se procijeniti plodnost?

This review critically comments on established and emerging methods of semen evaluation that would foresee the fertility of the ejaculate (neat or processed) or the male. Functional sperm testing through biomimetic in vitro assays are priority since these, by resembling events during sperm transport, storage and interaction with the female genital tract and the oocyte, best provide clues for sperm selection and the role of sperm sub-populations in the ejaculate. The review also focuses on the exploration of the genome, the transcriptome and the proteome of both spermatozoa and the seminal plasma which may help to unveil how spermatozoa and seminal plasma components would signal to the female and link to fertility and even prolificacy. Specific seminal plasma components, both among individuals and portions of the ejaculate, not only relate to sperm survival but also to signal the female immune system towards a differential immune tolerance warranting fertility.Ovaj pregledni članak pruža kritički osvrt na standardne i inovativne metode za procjenu kakvoće sjemena kako bi se predvidio oplodni potencijal ejakulata (nativnog ili obrađenog) i mužjaka. Funkcionalna testiranja spermija u in vitro uvjetima su nužna, budući da se slični procesi odvijaju tijekom transporta spermija, pohrane i interakcije sa ženskim spolnim sustavom i oocitama, jer pružaju uvid u ulogu pojedinih subpopulacija spermija u ejakulatu i time pomažu kod odabira spermija. Nadalje, ovaj se članak isto tako usredotočuje na istraživanje genoma, transkriptoma i proteoma spermija i sjemene plazme što može pomoći pri otkrivanju kako spermiji i molekule sjemene plazme mogu dati signal ženki i povezati to s plodnošću pa čak i s brojem potomaka. Specifične molekule sjemene plazme koje se razlikuju između jedinki između pojedinih frakcija ejakulata, povezane su s preživljavanjem spermija kao i s majčinom imunosnom tolerancijom prema spermijima što omogućuje plodnosti

Датчик угла наклона на основе MEMS-акселерометра

Материалы XVI Междунар. науч.-техн. конф. студентов, аспирантов и молодых ученых, Гомель, 28–29 апр. 2016 г

Localisation of the hyaluronan receptor CD44 in porcine cumulus cells during in vivo and in vitro maturation

Polyspermy is fairly common during porcine in vitro fertilisation (IVF), perhaps due to incomplete in vitro oocyte maturation (IVM). Porcine cumulus cells (CCs) layered around the oocyte produce large amounts of extracellular hyaluronan (HA) when forming an expanding cell cloud during the last phase of oocyte maturation. The specific actions of HA are mediated via HA-binding proteins (HABPs), such as CD44, which act as receptors. In this study using immunocytochemistry and western blotting we investigated the localisation of CD44 in CCs obtained from in vivo-matured pig cumulus–oocyte complexes (COCs) and compared it with that in CCs from immature COCs and of COCs subjected to IVM and IVF procedures. Immunolabelling of CD44 was absent or very weak in CCs from immature COCs but strongly present on the surface of the CCs obtained from in vivo, displaying a similar localisation in the in vitromatured COCs. In the latter, the labelling decreased but did not disappear in CCs 4 h after sperm co-incubation during IVF. Immunoblotting detected bands of between 73 and 88 kDa, corresponding to CD44, in the protein extract from in vivo CCs collected immediately prior to, or following spontaneous ovulation. The in vitro-matured CCs, however, presented bands ranging from 81 kDa to 88 kDa. Also, the bands found in the in vivo-matured CCs showed a larger variation of intensity and migration among animals than did the batches of in vitro-matured CCs. No CD44 band was detected on aliquots of the frozenthawed boar spermatozoa used for IVF. The results clearly demonstrate that the specific HA receptor CD44 is present in expanding CCs of in vivo-matured pig COCs, in relation to increasing amounts of inter-CC HA. The subtle differences in molecular weight and migration ability observed between in vivo and in vitro samples may relate to differences in glycosylation and thus explain differences in HA-binding ability, of consequence for optimising in vitro culture conditions.</p

Bicarbonate-Triggered In Vitro Capacitation of Boar Spermatozoa Conveys an Increased Relative Abundance of the Canonical Transient Receptor Potential Cation (TRPC) Channels 3, 4, 6 and 7 and of CatSper-γ Subunit mRNA Transcripts

Sperm capacitation is a stepwise complex biochemical process towards fertilization. It includes a crucial early calcium (Ca2+) transport mediated by CatSper channels and Canonical Transient Potential Channels (TRPC). We studied the relative abundance of mRNA transcripts changes of the CatSper β, γ and δ subunits and TRPC-channels 1, 3, 4, 6 and 7 in pig spermatozoa, after triggering in vitro capacitation by bicarbonate ions at levels present in vivo at the fertilization site. For this purpose, we analyzedfive5 ejaculate pools (from three fertile adult boars) before (control-fresh samples) and after in vitro exposure to capacitation conditions (37 mM NaHCO3, 2.25 mM CaCl2, 2 mM caffeine, 0.5% bovine serum albumin and 310 mM lactose) at 38 °C, 5% CO2 for 30 min. In vitro capacitation using bicarbonate elicits an increase in the relative abundance of mRNA transcripts of almost all studied Ca2+ channels, except CatSper-δ and TRPC1 (significantly reduced). These findings open new avenues of research to identify the specific role of each channel in boar sperm capacitation and elucidate the physiological meaning of the changes on sperm mRNA cargo

Le médecin, son patient et ses pairs:Une nouvelle approche de la relation thérapeutique

Les travaux relatifs à la relation thérapeutique ont jusqu'alors négligé un élément décisif: les relations entre médecins. Le cas de la cancérologie révèle que l'attention portée à ces relations est susceptible d'apporter un nouvel éclairage à la compréhension de la relation thérapeutique. En particulier, la concurrence entre médecins sur l'activité et sur la définition du bon traitement représente une incertitude supplémentaire majeure pour chaque médecin dans sa tentative de maîtriser la relation avec son patient. Dès lors, les stratégies médicales d'organisation et de réorganisation locale de la prise en charge peuvent s'analyser comme des tentatives de réduction de cette incertitude. Réciproquement, la relation au patient n'a pas pour seule fin la guérison mais constitue aussi un autre moyen de maîtriser cette incertitude et, consécutivement, d'améliorer les relations thérapeutiques futures : le patient est pour le médecin un moyen d'obtenir de l'information sur les comportements de ses pairs et un moyen d'échange pour entretenir des relations privilégiées avec certains d'entre eux