title: Ultrastructural markers of quality in human mature oocytes vitrified using cryoleaf and cryoloop.
abstract: This study describes and compares the possible effects of vitrification on the ultrastructural morphology of 20 human mature oocytes vitrified using two different supports, cryoleaf (n = 10) and cryoloop (n = 10). Fresh human mature oocytes (n = 15) were used as controls. Fresh and vitrified-warmed oocytes appeared rounded, with a homogeneous cytoplasm, an intact oolemma and a continuous zona pellucida. Sparse microvacuolization was only occasionally detected in fresh and vitrified-warmed oocytes, to the same extent. About 50% of the vitrified oocytes contained atypical, small and slender mitochondria-smooth endoplasmic reticulum aggregates, whereas a non-homogeneous microvillar pattern was observable in only 30% of the oocytes subjected to vitrification, regardless of the support utilized. Cortical granule content appeared generally reduced after vitrification, but cryoleaf-supported oocytes contained more cortical granules than cryoloop-supported oocytes (P < 0.05). Thus good overall preservation and virtual absence of cytoplasmic vacuolization seem to be the most relevant markers of quality in vitrified-warmed oocytes, using either support. In addition, cryoleaf-supported oocytes retained a higher number of cortical granules than cryoloop-supported oocytes. The variety of ultrastructural alterations recorded emphasizes the need for further studies aimed at assessing the actual tolerance of human oocytes to vitrification.
authors.affiliation: Department of Anatomy, Sapienza University, Rome 00161, Italy. stefania.nottola@uniroma1.it
authors.forename: S A
authors.initials: SA
authors.lastname: Nottola
authors.forename: G
authors.initials: G
authors.lastname: Coticchio
authors.forename: R
authors.initials: R
authors.lastname: Sciajno
authors.forename: A
authors.initials: A
authors.lastname: Gambardella
authors.forename: M
authors.initials: M
authors.lastname: Maione
authors.forename: G
authors.initials: G
authors.lastname: Scaravelli
authors.forename: S
authors.initials: S
authors.lastname: Bianchi
authors.forename: G
authors.initials: G
authors.lastname: Macchiarelli
authors.forename: A
authors.initials: A
authors.lastname: Borini
mesh_terms: D015415:Biomarkers; D002462:Cell Membrane / Q000187:drug effects / Q000648:ultrastructure*; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D005615:Freezing; D006801:Humans; D046529:Microscopy, Electron, Transmission; D009865:Oocytes / Q000187:drug effects / Q000648:ultrastructure*; D014617:Vacuoles / Q000187:drug effects / Q000648:ultrastructure*; D015044:Zona Pellucida / Q000187:drug effects / Q000648:ultrastructure
chemical_list: D015415:Biomarkers; D003451:Cryoprotective Agents