| dc.description.abstract |
The effect of calcium concentration on fertilization and activation wasexamined in oocytes injected in vitro with sperm.Oocytes were subjected to sperm injection, to sham injection or remaineduninjected, and were then cultured for 19 h in bicarbonate-buffered syntheticoviduct fluid (BSOF) without calcium, or containing either calcium chloride orcalcium ionophore. There was no difference in fertilization rates after ICSIwhen oocytes were cultured in vitro in media containingcalcium chloride or calcium ionophore but the rate was lower in calcium-freemedia. There was also no difference in the fertilization rate after ICSI whenoocytes were culturedin vivocompared with thatobservedin vitro in media containing calcium chloride orcalcium ionophore. In calcium chloride-treated oocytes, activation was inducedby mechanical injection, and in calcium ionophore-treated oocytes, by theionophore. In uninjected oocytes, calcium itself did not cause oocyteactivation. It is concluded that it is possible to induce activation by theinjection process, but that manipulation alone is inadequate to cause properoocyte activation unless calcium is also present. No difference in oocyteactivation between ICSI and sham injection was found, indicating that thesperm may play no role in the early events of oocyte activation. |
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