BACKGROUND<\/p>\n
In some couples, not all retrieved oocytes mature, even after prolonged in vitro<\/I> culture. The underlying mechanisms are not known, although ionophore treatment may alleviate metaphase I (MI) arrest in some mouse strains. We attempted to induce first polar body (PB) extrusion and fertilization using assisted oocyte activation (AOA) after ICSI in maturation-resistant human MI oocytes.<\/p>\n
METHODS<\/p>\n
Four ICSI patients are described in this retrospective study. A pilot study tested the calcium ionophore ionomycin (10 µM) on donated MI oocytes from patients with a normal number of metaphase II (MII) oocytes. Subsequently, ionomycin was used to induce first PB extrusion in two patients showing maturation-resistant MI oocytes. AOA, by calcium injection and ionomycin exposure, was applied when mature oocytes were available. Oocytes were analysed by polarized microscopy and immunostaining.<\/p>\n
RESULTS<\/p>\n
Ionomycin induced the first PB extrusion in MI oocytes from patients with a normal number of retrieved MII oocytes, while extended in vitro<\/I> culture failed to achieve the MII stage. Similarly, ionomycin induced first PB extrusion in one of two patients with recurrent maturation-resistant MI oocytes. Use of ICSI combined with AOA on MII oocytes matured in vitro<\/I> or in vivo<\/I> resulted in failed or abnormal fertilization with no further embryo cleavage potential. Highly abnormal spindle and chromosome configurations were observed in MI maturation-resistant oocytes, in contrast to control MI oocytes.<\/p>\n
CONCLUSIONS<\/p>\n
Ionophore induced first PB extrusion in MI oocytes from patients without maturation arrest but to a lower extent in maturation-resistant MI oocytes. Immunofluorescence staining and confocal analysis revealed, for the first time, highly abnormal spindle\/chromosomal structures that may be responsible for this maturation arrest.<\/p>\n","protected":false},"excerpt":{"rendered":"
BACKGROUND In some couples, not all retrieved oocytes mature, even after prolonged in vitro culture. The underlying mechanisms are not known, although ionophore treatment may alleviate metaphase I (MI) arrest in some mouse strains. We attempted to induce first polar … Continue reading