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

Objective: To evaluate the imaging of cytoplasmic movements in human oocytes as a potential method to monitor the pattern of Ca2+ oscillations during activation. Design: Test of a laboratory technique. Setting: University medical school research laboratory. Patient(s): Donated unfertilized human oocytes from intracytoplasmic sperm injection (ICSI) cycles. Intervention(s): Microinjection of oocytes with phospholipase C (PLC) zeta (zeta) cRNA and a Ca2+-sensitive fluorescent dye. Main Outcome Measure(s): Simultaneous detection of oocyte cytoplasmic movements using particle image velocimetry (PIV) and of Ca2+ oscillations using a Ca2+-sensitive fluorescent dye. Result(s): Microinjection of PLC zeta cRNA into human oocytes that had failed to fertilize after ICSI resulted in the appearance of prolonged Ca2+ oscillations. Each transient Ca2+ concentration change was accompanied by a small coordinated movement of the cytoplasm that could be detected using PIV analysis. Conclusion(s): The occurrence and frequency of cytoplasmic Ca2+ 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 Ca2+ oscillations in human zygotes. (Fertil Steril (R) 2012; 97: 742-7. (C) 2012 by American Society for Reproductive Medicine.)