Post-warming competence of in vivo matured rabbit oocytes treated with cytoskeletal stabilisation (Taxol) and cytoskeletal relaxant (Cytochalasin B) before vitrification

Abstract

[EN] Contents The aim of this study was to investigate the effect of Taxol and Cytochalasin B on the spindle, chromosome configuration and development to blastocyst stage after parthenogenesis activation of in vivo matured rabbit oocytes after vitrification. Oocytes were randomized into four groups: oocytes treated with Cytochalasin B or Taxol before vitrification, oocytes without treatment before vitrification and fresh oocytes. Oocytes were vitrified using Cryotop method, and meiotic spindle and chromosomal distribution were assessed with a confocal laser scanning microscopy. To determine oocyte competence, in vitro development of oocytes was assessed with parthenogenesis activation. There were no significant differences in the frequencies of normal spindle (33.0%, 31.0% and 32.6%, for non-treated, Taxol-treated and Cytochalasin B-treated oocytes, respectively) and chromosome (48.3%, 46.6% and 34.8%, for non-treated, Taxol-treated oocytes and Cytochalasin B-treated oocytes respectively) in vitrified groups, but significantly lower than those of fresh group (89.7% and 90.2%, for normal spindle and chromosome organization, respectively). No statistical differences were found in the cleavage and blastocyst development rates between non-treated and Taxol-treated oocytes (7.7% and 1.5% and 13.7% and 4.6%, for non-treated and Taxol-treated oocytes, respectively), although they were significantly lower than in the fresh group (42.3% and 32.1%, for cleavage and blastocyst development, respectively). Oocytes treated with Cytochalasin B failed to reach blastocyst stage. Normal spindle, chromosome configuration and blastocyst development of in vivo matured rabbit oocytes were damaged in vitrification, which was not improved by Taxol and Cytochalasin B pre-treatment before vitrification. Moreover, a detrimental effect on blastocyst development of Cytochalasin B pre-treatment before vitrification was observed.