title: Rescue of failed oocyte activation after ICSI in a mouse model of male factor infertility by recombinant phospholipase Cζ.
abstract: Artificial oocyte activation to overcome failed fertilization after intracytoplasmic sperm injection (ICSI) in human oocytes typically employs Ca(2+) ionophores to produce a single cytosolic Ca(2+) increase. In contrast, recombinant phospholipase Czeta (PLCζ) causes Ca(2+) oscillations indistinguishable from those occurring during fertilization, but remains untested for its efficacy in a scenario of ICSI fertilization failure. Here, we compare PLCζ with other activation stimuli in a mouse model of failed oocyte activation after ICSI, in which heat-treated sperm are injected into mouse oocytes. We show that increasing periods of 56 °C exposure of sperm produces a progressive loss of Ca(2+) oscillations after ICSI. The decrease in Ca(2+) oscillations produces a reduction in oocyte activation and embryo development to the blastocyst stage. We treated such oocytes that failed to activate after ICSI either with Ca(2+) ionophore, or with Sr(2+) media which causes Ca(2+) oscillations, or we injected them with recombinant human PLCζ. All these treatments rescued oocyte activation, although Sr(2+) and PLCζ gave the highest rates of development to blastocyst. When recombinant PLCζ was given to oocytes previously injected with control sperm, they developed normally to the blastocyst stage at rates similar to that after control ICSI. The data suggest that recombinant human PLCζ protein is an efficient means of rescuing oocyte activation after ICSI failure and that it can be effectively used even if the sperm already contains endogenous Ca(2+) releasing activity.
authors.affiliation: Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK.
authors.forename: Randa
authors.initials: R
authors.lastname: Sanusi
authors.affiliation: Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK Present address: TopChoice Medical, TopChoice Building, 327 Tianmushan Road, Hangzhou City, Zhejiang Province, China.
authors.forename: Yuansong
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK.
authors.forename: Michail
authors.initials: M
authors.lastname: Nomikos
authors.affiliation: Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK.
authors.forename: F Anthony
authors.initials: FA
authors.lastname: Lai
authors.affiliation: Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK swannk1@cf.ac.uk.
authors.forename: Karl
authors.initials: K
authors.lastname: Swann
mesh_terms: D000818:Animals; D001755:Blastocyst; D020013:Calcium Signaling / Q000187:drug effects*; D004195:Disease Models, Animal; D047108:Embryonic Development / Q000187:drug effects; D005260:Female; D005306:Fertilization / Q000187:drug effects; D006358:Hot Temperature; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology*; D015759:Ionomycin / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D054801:Phosphoinositide Phospholipase C / Q000494:pharmacology*; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods; D013324:Strontium / Q000494:pharmacology
chemical_list: D007476:Ionophores; D011993:Recombinant Fusion Proteins; D015759:Ionomycin; C499235:PLCZ1 protein, human; D054801:Phosphoinositide Phospholipase C; D013324:Strontium
keywords: ICSI; PLCζ; fertilization; oocyte; sperm