Marín-Briggiler C I, Vazquez-Levin M H, Gonzalez-Echeverría F, Blaquier J A, Tezón J G, Miranda P V
Instituto de Biología y Medicina Experimental, (1428) Buenos Aires, Argentina Fertilab, (1116) Buenos Aires, Argentina.
Biol Reprod. 1999 Sep;61(3):673-80. doi: 10.1095/biolreprod61.3.673.
The ability of strontium (Sr(2+)) to replace calcium (Ca(2+)) in maintaining human sperm function has still not been completely characterized. In the present study, acrosome reaction (AR) inducibility in response to human follicular fluid (hFF) was compared in spermatozoa incubated in either Ca(2+)- or Sr(2+)-containing media. Other events related to sperm capacitation, such as protein tyrosine phosphorylation and hyperactivation as well as zona pellucida (ZP) recognition under both conditions, were also analyzed. Spermatozoa incubated overnight in the presence of Sr(2+) were unable to undergo the AR when exposed to hFF. Nevertheless, when spermatozoa were incubated under this condition and then transferred to medium with Ca(2+), sperm response to hFF was similar to that of cells incubated throughout in the presence of Ca(2+). The sperm protein tyrosine phosphorylation patterns and the percentages of sperm motility and hyperactivation were similar after incubation in Ca(2+)- or Sr(2+)-containing media. Under both conditions, the same binding capacity to homologous ZP was observed. Similar results were obtained when EGTA was added in order to chelate traces of Ca(2+) present in Sr(2+) medium. From these results, it can be concluded that Sr(2+) can replace Ca(2+) in supporting capacitation-related events and ZP binding, but not hFF-induced AR of human spermatozoa.
在维持人类精子功能方面，锶（Sr(2+)）替代钙（Ca(2+)）的能力尚未完全明确。在本研究中，比较了在含Ca(2+)或含Sr(2+)培养基中孵育的精子对人卵泡液（hFF）诱导顶体反应（AR）的能力。还分析了与精子获能相关的其他事件，如蛋白质酪氨酸磷酸化和超活化，以及在这两种条件下对透明带（ZP）的识别。在Sr(2+)存在下过夜孵育的精子，暴露于hFF时无法发生AR。然而，当精子在此条件下孵育后再转移到含Ca(2+)的培养基中时，精子对hFF的反应与全程在Ca(2+)存在下孵育的细胞相似。在含Ca(2+)或含Sr(2+)的培养基中孵育后，精子蛋白质酪氨酸磷酸化模式、精子活力和超活化百分比相似。在这两种条件下，观察到对同源ZP的相同结合能力。当添加乙二醇双四乙酸（EGTA）以螯合Sr(2+)培养基中存在的微量Ca(+)时，也获得了类似结果。从这些结果可以得出结论，Sr(2+)可以替代Ca(2+)支持与获能相关的事件和ZP结合，但不能替代Ca(2+)支持hFF诱导的人类精子AR。
