Sperm volumetric dynamics during in vitro capacitation process in bovine spermatozoa

Abstract

Previous studies have demonstrated that sperm head morphometry can be used as a potential diagnostic tool for detecting biophysical changes associated with sperm viability in bovine spermatozoa. In this study, sperm head morphometry was used to investigate its value as a biophysical marker for detecting volumetric changes in bovine spermatozoa under in vitro capacitating and non-capacitating incubation conditions. To further test this hypotesis, aliquots of pooled, washed bovine sperm were incubated in either Tyrode's complete medium with heparin (TCMH; a capacitating medium containing Ca 2+ , NaHCO 3 and heparin), Tyrode's complete medium heparin-free (TCM; a medium containing just Ca 2+ and NaHCO 3 ) or Tyrode's basal medium (TBM; a non-capacitating medium free of Ca 2+ , NaHCO 3 and heparin, used as control). Aliquots of sperm were processed for morphometric analysis at different incubation-time intervals (0, 3 and 6 h at 38°C), and the chlortetracycline assay was used simultaneously to confirm the ability of the sperm to undergo capacitation (B pattern) and the acrosome reaction (AR pattern) status in each medium. After 3 h of incubation under TCMH conditions, a significant increase was observed in the percentage of B and AR patterns and a significant decrease was found in all sperm morphometric parameters ( P < 0.01). Interestingly, after 6 h of incubation in TCMH, the percentage of B and AR patterns increased drastically over time and marked differences were found in the dimensional and shape parameters, which were significantly smaller compared with TBM or TCM media ( P < 0.001). Significant correlations were observed between sperm size and AR pattern (r = −0.875, P < 0.01). In conclusion, sperm head morphometry can be used as a potential biophysical marker for detecting volumetric changes during capacitation process in bovine spermatozoa.

Comparison of the structure of chinchilla sperm isolated from semen and from the tail of the epididymis

“…Many studies indicate a relationship between sperm dimensions and fertility in horses (Hidalgo, Rodríguez, Dorado, & Soler, ; Phetudomsinsuk, Sirinarumitr, Laikul, & Pinyopummin, ), in which fertility disorders have been positively correlated with increased sperm head size (Gravance, Liu, Davis, Hughes, & Casey, ). The subject has also been taken up with regard to fertility in pigs (Saravia et al, ), bulls (Garcia‐Herreros & Leal, ) and dogs (Núñez‐Martínez, Moran, & Peña, ). Differences in head size between fertile and infertile males have been detected in various species (Casey, Gravance, Davis, Chabot, & Liu, ).…”

Mammalian sperm capacitation: In vivo and in vitro juxtaposition

“…Although the in vivo condition is considered to be more efficient as one capacitated sperm is enough for the completion of fertilization for each oocyte (Muro et al, 2016), in vitro capacitation medium for mammalian sperm has also been continuously refined through the introduction of several capacitation inducers and modification of procedure with different approach, as compiled in Table 3. (García-Álvarez et al, 2015;García-Herreros and Leal, 2014;Lukoseviciute et al, 2004;Parrish et al, 1988). There is also an observable trend where the consideration of the use of capacitation inducers leads to recreating the physiological environment of the female genital tract (Chaves et al, 2021), using substances that have been identified to modulate sperm capacitation in vivo such as oviductal fluid (OF) (Navarro-Serna et al, 2021), creatine (Umehara et al, 2018), and the involvement of hormones (estrogen and progesterone) (García-Álvarez et al, 2015).…”

Current status and potential of morphometric sperm analysis

“…Some authors have explored the morphological response to diluting or washing the sperm sample,105106 to capacitation107 or to cryopreservation 26108109110…”

“…reported how boar spermatozoa in the female reproductive tract are selected on the basis of their size and shape, with those with a larger head and longer tail being those reaching the fertilization site. For sperm morphometric changes during capacitation, García-Herreros and Leal107 reported that the induction of in vitro capacitation in bovine spermatozoa modified sperm head morphometry. As capacitated spermatozoa showed a decrease in all sperm head size and shape parameters, the authors concluded that sperm head morphometry is an objective diagnostic tool for sperm assessment during capacitation.…”