Exposure of human sperm to low-calcium medium enhances fertilizing ability.
This investigation was conducted to evaluate whether exposure of human sperm to low calcium enhances the fertilizing ability. When sperm from normal semen samples were preincubated in low-calcium mBWW medium for 1 h, the percentages of live acrosome-reacted sperm after 4 and 6 h of culture were significantly higher than control (5.0 +/- 0.5 vs. 3.2 +/- 0.3% and 6.0 +/- 0.5 vs. 4.2 +/- 0.3%, p < .05). The penetration rate (%P) and fertility index (FI) in zona-free hamster egg sperm penetration assay significantly increased, compared to control (%P: 66.4 +/- 9.0 vs. 42.7 +/- 8.1%; FI: 1.69 +/- 0.19 vs. 1.34 +/- 0.11; p < .01). When low-calcium treatment was used for human in vitro fertilization and embryo transfer (IVF-ET) for male infertility, the fertilization and pregnancy rates were significantly higher than those in control. The results indicate that preincubation of human sperm in low-calcium medium enhances their fertilizing ability. This method is a simple and useful for preparing sperm from subfertile men for human IVF-ET.
Department of Obstetrics and Gynecology, School of Medicine, University of Tokushima, Kuramoto-cho, Japan.
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S
Nishida
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Yamano
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Aono
D000177:Acrosome / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D006224:Cricetinae; D003470:Culture Media; D004624:Embryo Transfer; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D012016:Reference Values; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects*
D003470:Culture Media; D002118:Calcium