Search

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- Subunit mRNA Transcripts Presently, knowing the composition of the female tract place where sperm capacitation occurs and the molecules involved in either of the two pathways of the capacitation process, in vitro capacitation can be performed in most of the mammalian species. Following centrifugation (5000× I g i , 5 min), the sperm pellets of both control and in vitro capacitated samples were stored at -80 °C until further analysis (Ultra Low Freezer; Haier Inc., Qingdao, China) for analyzing all parameters: sperm evaluation (motility, viability and mitochondrial status) mRNA expression, cAMP and PKA. However, mRNA abundance in mature sperm does not necessarily correlate with the quantity of the protein expressed in the sperm, and more studies are needed to confirm the functional significance of the expression of Ca SP 2+ sp channels' mRNA in the spermatozoa. The capacitation events increase protein-tyrosine phosphorylation in the sperm tail [[12]], which appears to be related to the accompanying hyper-activation of sperm motility [[13], [15]]. [Extracted from the article]

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.