The effect of vitrification on maturation and viability capacities of immature human oocytes

摘要

Background: 15 % of oocytes collected from Assisted Reproductive Technology (ART) cycles are immature. These oocytes may be matured following in vitro maturation (IVM) program. It is possible to cryopreserve the immature oocytes for further use in ART after application of IVM. Objective: The aim was to determine the maturation rate and viability of human oocytes that were matured in vitro after vitrification program. Materials and methods: 63 women (19-43 years old) who underwent controlled ovarian stimulation for ART were included in this study. 53 immature oocytes were used for fresh group (fIVM) and 50 immature oocytes for vitrification group (vIVM). The maturation medium was Ham's F10 supplemented with 0.75 IU FSH, 0.75 IU LH and 40 % human follicular fluid (HFF). After 36 h, maturation and morphology of all oocytes were assessed. Also, the oocyte viability was assessed using PI/Hoechst immunostaining technique. Results: The maturation rates were reduced in vIVM group (56.0 %) in comparison to fIVM group (88.7 %; P 0.001). Oocyte viability rate were also reduced in vIVM group (56.0 %) in comparison to fIVM (86.8 %, P 0.007). Conclusions: Cryopreservation via vitrification reduced both the maturation capacity and viability of human oocytes in IVM technology. It is, therefore, recommended to apply IVM on fresh immature oocytes, instead.