The effect of vitrification on maturation and ultrastructure of in-vitro matured human oocytes

Aim: The aim of this study was to describe the possible effects of vitrification on maturation rate and ultrastructural morphology of in-vitro matured human oocytes.
Material and A total of 292 immature Germinal Vesicle (GV) and Metaphase I (MI) oocytes obtained from infertile patients were allocated into two groups: (i) GV oocytes (n=145), (ii) MI oocytes (n=147) . Oocytes were first vitrified and then matured in-vitro. Supernumerary fresh in-vivo matured oocytes (n=10) were used as control. in-vitro maturation media was Ham’s F10 supplemented with FSH and human follicular fluid. After 36h of incubation, the oocytes were investigated for nuclear maturation and ultrastructural changes .
The rate of survival and degeneration was significantly higher in Metaphase I than GV group. But, Oocyte maturation rates were not significant between groups (P Freeze/thawing procedures are associated with ultrastructural alterations in specific oocyte microdomains, presumably related to the reduced competence of cryopreserved oocytes to maturation.