Mitochondrial behaviors in the vitrified mouse oocyte and its parthenogenetic embryo: effect of Taxol pretreatment and relationship to competence

Objective To investigate the effect of Taxol pretreatment on mitochondrial behaviors in vitrified mouse mature oocytes and their parthenogenetic embryos. Design Experimental animal study. Setting University research laboratory and state key laboratory. Animal(s) Sexually mature female Kunming white strain mice. Intervention(s) Taxol before vitrification group (Tax). Oocytes were pretreated with M 2 containing 1 mmol/L Taxol for 2 minutes at 37C and then vitrified-warmed using the OPS vitrification procedure. Both ED solution and EDFS30 solution contained 1 mmol/L Taxol. Main Outcome Measure(s) Mitochondrial behaviors examined by fluorescence microscopy technology and fluorescence recovery after photobleaching (FRAP) technology. Result(s) In the control group, mitochondria were homogeneously distributed, in slow movement in oocytes, and perinuclearly distributed in 42.6% (n = 115) of their parthenogenetic two-cell embryos. Mitochondria from the toxicity group showed similar localization and movement to those of the control group, but not in the vitrification group. The perinuclear mitochondrial localization pattern of two-cell embryos was statistically significantly lower in both the toxicity (27.2%) and vitrification groups (19.8%) than in the control group. After parthenogenetic activation, the blastocyst formation rate of oocytes in the treated groups (28.1 to 48.6%) was statistically significantly lower than that of control (61.2%), but the rate of Taxol group (47.9%) was statistically significantly higher than that in the vitrification group (28.1%). Conclusion(s) Taxol pretreatment before vitrification helps to reduce the mitochondrial disturbance induced by vitrification in oocytes and their parthenogenetic early-stage embryo.