Acrosome-reacted human sperm in insemination medium do not bind to the zona pellucida of human oocytes.
In the literature there is still confusion whether acrosome-reacted sperm in medium can initiate primary binding to human zona pellucida (ZP). The ability of acrosome-reacted sperm to bind to ZP in vitro can be deduced by measuring the acrosome reaction (AR) of ZP-bound sperm compared with sperm in medium after incubation under different conditions inhibiting the ZP-induced AR. Motile sperm from fertile men, normospermic men and infertile men diagnosed with disordered ZP-induced AR (DZPIAR) were selected by swim-up (2 x 10(6) in 1 mL medium) and incubated for 1-2 h with four oocytes from failed in vitro fertilization (IVF). The acrosome status of sperm was assessed using pisum sativum agglutinin labelled with fluorescein. The ZP-induced AR was inhibited in experiments using sperm from DZPIAR patients, hyper-osmotic medium (400 mOsm/kg) and medium containing soybean trypsin inhibitor (SBTI; 4 mg/mL). Pre-treatment with calcium ionophore was used to create a sperm population with elevated AR. In all experiments with factors inhibiting the ZP-induced AR, the AR was significantly lower for ZP-bound sperm compared with sperm in medium: DZPIAR patients 4% vs. 15%, hyper-osmotic medium 3% vs. 12%, SBTI 2% vs. 12% and SBTI 3% vs. 23% after treatment with calcium ionophore. In conclusion, acrosome-reacted sperm in vitro have significantly reduced, in fact probably zero ability to bind to the ZP.
Liu
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DY
University of Melbourne Department of Obstetrics and Gynaecology, Reproductive Services, Royal Women's Hospital and Melbourne IVF, Vic., Australia. dyl@unimelb.edu.au
Garrett
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Baker
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HW
D020101:Acrosome Reaction / Q000502:physiology*; D003470:Culture Media; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology; D008297:Male; D009994:Osmolar Concentration; D013081:Sperm Motility; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*; D014360:Trypsin Inhibitor, Kunitz Soybean / Q000494:pharmacology; D015044:Zona Pellucida / Q000502:physiology*
D003470:Culture Media; D014360:Trypsin Inhibitor, Kunitz Soybean