Phospholipase C-ζ-induced Ca2+ oscillations cause coincident cytoplasmic movements in human oocytes that failed to fertilize after intracytoplasmic sperm injection

School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom.
Fertility and sterility (Impact Factor: 4.59). 01/2012; 97(3):742-7. DOI: 10.1016/j.fertnstert.2011.12.013
Source: PubMed


To evaluate the imaging of cytoplasmic movements in human oocytes as a potential method to monitor the pattern of Ca(2+) oscillations during activation.
Test of a laboratory technique.
University medical school research laboratory.
Donated unfertilized human oocytes from intracytoplasmic sperm injection (ICSI) cycles.
Microinjection of oocytes with phospholipase C (PLC) zeta (ζ) cRNA and a Ca(2+)-sensitive fluorescent dye.
Simultaneous detection of oocyte cytoplasmic movements using particle image velocimetry (PIV) and of Ca(2+) oscillations using a Ca(2+)-sensitive fluorescent dye.
Microinjection of PLCζ cRNA into human oocytes that had failed to fertilize after ICSI resulted in the appearance of prolonged Ca(2+) oscillations. Each transient Ca(2+) concentration change was accompanied by a small coordinated movement of the cytoplasm that could be detected using PIV analysis.
The occurrence and frequency of cytoplasmic Ca(2+) oscillations, a critical parameter in activating human zygotes, can be monitored by PIV analysis of cytoplasmic movements. This simple method provides a novel, noninvasive approach to determine in real time the occurrence and frequency of Ca(2+) oscillations in human zygotes.

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Available from: Michail Nomikos
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    • ") . Such cytoplasmic flows have also been described in human 1 - cell embryos ( Swann et al . , 2012 ) , although there are still no data correlating cytoplasmic dynamics with developmental quality of the human embryos ."
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    • "This pattern of localization supports the role of PLCz as the SOAF, since after the acrosome reaction, the equatorial region of the sperm membrane is exposed, adheres to and fuses with the oolemma (Barroso et al., 2009). In strong support of the role of PLCz, is the fact that mammalian oocytes can be activated following microinjection of either recombinant PLCz or complementary RNA (cRNA) encoding PLCz (Yoon et al., 2008; Swann et al., 2012; Nomikos et al., 2013b). "
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    • "Another study showed that the microinjection of oocyte activation deficient spermatozoa along with exposure to calcium ionophore generated live offspring [133]. Furthermore, microinjection of oocytes, that failed to fertilize with ICSI, with PLC␨ cRNA resulted in the appearance of prolonged Ca 2+ oscillations where each transient Ca 2+ wave was accompanied by a small coordinated cytoplasmic movement [172]. These studies further solidified the idea that PLC␨ is a great candidate as a clinical therapeutic solution that could avoid potentially deleterious effects associated with AOA, which use the non-physiological stimuli. "
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