Characterization of calcium oscillation patterns in caprine oocytes induced by IVF or an activation technique used in nuclear transfer
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- 作者：Teru Jellerette ; David Melican ; Robin Butler ; Scott Nims ; Carol Ziomek ; Rafael Fissore and William Gavin
- 关键词：Developmental biology ; Calcium ; Embryo ; Sperm ; Goat
- 刊名：Theriogenology
- 出版年：2006
- 出版时间：May 2006
- 年：2006
- 卷：65
- 期：8
- 页码：1575-1586
- 全文大小：384 K
文摘
Routine activation of nuclear transfer (NT) eggs involves the application of a single intracellular calcium [Ca2+d;i rise, stimulated by an electrical pulse, as opposed to [Ca2+d;i oscillations, which is the natural mode of sperm-induced activation at fertilization in all mammalian species tested to date. It has yet to be shown that caprine oocytes exhibit an increase in calcium at fertilization in a manner similar to other mammals. The objective of the present study was to evaluate and characterize the ([Ca2+d;i) oscillation patterns of caprine metaphase II (MII) oocytes during IVF and during an activation techniques used in nuclear transfer. Additionally, the effect of cytochalasin B (cyto B) in the NT process was evaluated for its impact on [Ca2+d;i oscillations and subsequent embryo development. Mature in vitro and in vivo derived caprine oocytes were activated by 5 μM ionomycin, an electrical pulse(s), or IVF. The intracellular Ca2+ response was determined using the [Ca2+d;i indicator Fura-2 dextran (Fura-2D). Ova treated with ionomycin or stimulated by an electrical pulse exhibited a single [Ca2+d;i rise, whereas IVF-derived oocytes showed oscillations. IVF [Ca2+d;i showed some variation, with 62 % of in vitro matured oocytes exhibiting oscillations, whereas 8 % of in vivo matured oocytes exhibited oscillations demonstrating a correlation between [Ca2+d;i responses and maturation technique. Knowing the [Ca2+d;i profile of activated eggs, one may be able to optimize the activation methodology used in a production nuclear transfer setting which could potentially improve development to term for NT embryos.