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19 January, 2021
The ability to mount and respond to an appropriate Ca2+ signal at fertilisation is largely unchanged by advancing maternal age, but subtle changes in Ca2+ handling occur that may have more substantial impacts upon commonly used means of parthenogenetic ac
19 January, 2021

Ca2+ dynamics in oocytes from naturally-aged mice

 

Jenna Haverfield1, Shoma Nakagawa1, Daniel Love2, Elina Tsichlaki3, Michail Nomikos2, F. Anthony Lai2, Karl Swann2 & Greg FitzHarris1,3

  1. Centre Recherche Centre Hospitalier Université de Montréal, Montreal, Québec, H2X 0A9, CanadA, Department of Obstetrics and Gynaecology, University of Montréal, Montréal, Québec, H3T 1J4, Canada
  2. Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, CF14 4XN, UK
  3. Department of Cell and Developmental Biology, University College London, WC1E 6BT, London, UK

 

The ability of human metaphase-II arrested eggs to activate following fertilisation declines with advancing maternal age. Egg activation is triggered by repetitive increases in intracellular Ca2+ concentration ([Ca2+]i) in the ooplasm as a result of sperm-egg fusion. We therefore hypothesised that eggs from older females feature a reduced ability to mount appropriate Ca2+ responses at fertilisation. To test this hypothesis we performed the first examination of Ca2+ dynamics in eggs from young and naturally-aged mice. Strikingly, we find that Ca2+stores and resting [Ca2+]i are unchanged with age. Although eggs from aged mice feature a reduced ability to replenish intracellular Ca2+ stores following depletion, this difference had no effect on the duration, number, or amplitude of Ca2+ oscillations following intracytoplasmic sperm injection or expression of phospholipase C zeta. In contrast, we describe a substantial reduction in the frequency and duration of oscillations in aged eggs upon parthenogenetic activation with SrCl2. We conclude that the ability to mount and respond to an appropriate Ca2+ signal at fertilisation is largely unchanged by advancing maternal age, but subtle changes in Ca2+ handling occur that may have more substantial impacts upon commonly used means of parthenogenetic activation.

 

 

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Publisher: Haverfield et al., Sci Rep. 2016; 6: 19357

Full text links: https://rdcu.be/cnzxd 

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