Possible ability of bovine follicular fluid to attract migrating bull spermatozoa

Abstract

AimTo examine the potential of bovine follicular fluid (BFF) to attract bull spermatozoa.MethodsThe ability of the BFF to attract bull sperm was evaluated by observing changes in sperm migration after being placed in a cross‐column chamber. The movement parameters of the heads and flagella of the sperm that were attracted to the BFF were analyzed by using the Computer Assisted Sperm Analysis system.ResultsIt was observed that 61.6% of the bull sperm migrated toward the BFF when the BFF was used at a concentration of 0.1%, but 67.2% of the sperm did not migrate toward the BFF at a concentration of 10%. Relatively larger numbers of both precapacitated and postcapacitated bull sperm migrated toward the BFF (0.1%). The ability of the 0.1% BFF to attract sperm probably affected both the normal artificial insemination (AI) fertility sperm and the poor AI fertility spermatozoa. The flagellar curvilinear ratio of the sperm winding to the 0.1% BFF was significantly higher than that of the prewinding sperm.ConclusionThese results could suggest that BFF potentially attracts bull sperm at a certain concentration, irrespective of the capacitation status of the sperm. Although the mechanism by which this attraction occurs remains unclear, these data imply that it could be related to BFF‐dependent changes in the sperm flagellar curvilinear ratio.

Stromal cell-derived factor 1 regulates in vitro sperm migration towards the cumulus-oocyte complex in cattle

“…It was also found that SDF1 is not a regulatory factor of sperm protein tyrosine phosphorylation, which is a major indicator of sperm capacitation, or the acrosome reaction (S5 Fig). According to our results, <5% of total sperm were attracted by SDF1, which was in agreement with previous studies suggesting that only a small fraction of the sperm population is chemotactically responsive in mammals [6,18,33]. In fact, the percentage of chemotactic sperm in the total sperm population is 2%-12% in humans [34].…”

“…Several studies have demonstrated that only capacitated sperm, which possess the potential to undergo the acrosome reaction and hyperactivation, are chemotactic in humans and mice [32,33,35]. However, in cattle, the capacitated state is unlikely to be relevant to sperm chemotaxis because this study and a previous study showed that sperm capacitation treatment is unnecessary to induce sperm chemotaxis in cattle [18]. It should be noted that in this study, the sperm medium contained caffeine that induces hyperactivation immediately regardless of the sperm capacitated state (S6 Fig) [36].…”

“…Some studies have suggested that follicular fluid attracts bovine sperm [17,18]. Progesterone exists in mammalian follicular fluids and a well-known chemoattractant [19].…”

Characterization of extracellular Ca2+‐dependent full‐type hyperactivation in ejaculated boar spermatozoa preincubated with a cAMP analog

“…This synchronicity allowed for the identification of extracellular Ca 2+ entry via CatSper channels of the flagellar principal piece, and Ca 2+ release from internal storage within the connecting piece as important initiators of hyperactivation as well as sperm fertility (Carlson et al, 2003(Carlson et al, , 2005Marquez, Ignotz, & Suarez, 2007). Conversely, achieving high rates of synchronous hyperactivation in ejaculated spermatozoa of livestock is not easily done by incubation in capacitation medium containing bicarbonate (Marquez & Suarez, 2004;McPartlin, Suarez, Czaya, Hinrichs, & Bedford-Guaus, 2009;Mondal, Takagi, Baba, & Hamano, 2017;Umezu et al, 2016), so regulatory mechanisms for their hyperactivation are instead investigated in samples pharmacologically treated with possible elevators of intracellular Ca 2+ (e.g., the Ca 2+ ionophore A23187; procaine; 4-aminopyridine (4-AP); caffeine; thapsigargin; or thimerosal) (Ho & Suarez, 2001;Marquez & Suarez, 2004;McPartlin et al, 2009;Tateno & Mikamo, 1987;Schmidt & Kamp, 2004;Suarez, Dai, DeMott, Redfern, & Mirando, 1992). This extra step limits out understanding how sperm alterations lead to their hyperactivation in livestock.…”

<b>Caracterização das subpopulações e atributos espermáticos como método preditivo de desempenho na produção <i>in vitro</i> de embriões em bovinos</b>

“…Estes resultados são sugestivos de cinética de hiperativação, pois não há consenso sobre os valores destes parâmetros que caracterizam este tipo de cinética espermática na espécie bovina, sendo encontrados valores divergentes na literatura (SHOJAEI et al, 2012;VAN DER HORST, 2014;KANNO et al, 2017;MONDAL et al, 2017). A dificuldade no estabelecimento destes valores de referência e ainda, a comparação de resultados em diferentes estudos, é de grande complexidade devido a diversos fatores que influenciam na acurácia e precisão desta avaliação, como: metodologia, uso de diferentes tipos de aparelhos e configurações do software, manipulação de amostras como meio diluir e seleção espermática (SHOJAEI et al, 2012;WABERSKI, 2014;ISHIJIMA, 2015;DEL GALLEGO et al, 2017;KANNO et al, 2017).…”