Freeze/thaw stress induces organelle remodeling and membrane recycling in cryopreserved human mature oocytes

Stefania Annarita Nottola, Elena Albani, Giovanni Coticchio, Maria Grazia Palmerini, Caterina Lorenzo, Giulia Scaravelli, Andrea Borini, Paolo Emanuele Levi-Setti, Guido Macchiarelli

Research output: Contribution to journalArticlepeer-review


Purpose: Our aim was to evaluate the ultrastructure of human metaphase II oocytes subjected to slow freezing and fixed after thawing at different intervals during post-thaw rehydration. Methods: Samples were studied by light and transmission electron microscopy. Results: We found that vacuolization was present in all cryopreserved oocytes, reaching a maximum in the intermediate stage of rehydration. Mitochondria-smooth endoplasmic reticulum (M-SER) aggregates decreased following thawing, particularly in the first and intermediate stages of rehydration, whereas mitochondria-vesicle (MV) complexes augmented in the same stages. At the end of rehydration, vacuoles and MV complexes both diminished and M-SER aggregates increased again. Cortical granules (CGs) were scarce in all cryopreserved oocytes, gradually diminishing as rehydration progressed. Conclusions: This study also shows that such a membrane remodeling is mainly represented by a dynamic process of transition between M-SER aggregates and MV complexes, both able of transforming into each other. Vacuoles and CG membranes may take part in the membrane recycling mechanism.

Original languageEnglish
Pages (from-to)1-12
Number of pages12
JournalJournal of Assisted Reproduction and Genetics
Publication statusAccepted/In press - Sep 1 2016


  • Cryopreservation
  • Human
  • Oocyte
  • Organelles
  • Ultrastructure
  • Vacuoles

ASJC Scopus subject areas

  • Reproductive Medicine
  • Genetics
  • Obstetrics and Gynaecology
  • Developmental Biology
  • Genetics(clinical)


Dive into the research topics of 'Freeze/thaw stress induces organelle remodeling and membrane recycling in cryopreserved human mature oocytes'. Together they form a unique fingerprint.

Cite this