Ultrastructure of human oocytes after in vitro maturation

Abstract
Study hypothesis: How does the ultrastructure of human oocytes matured in vitro compare with oocytes collected from women after full hormonal stimulation?
Study finding: The ultrastructure of human oocytes matured in vitro is largely, but not entirely, similar to those matured in vivo.
Main results and the role of chance: All oocytes had normal ooplasm showing uniform distribution of organelles. Mitochondrial morphology appeared similar between the maturation conditions. Cortical granules were found typically stratified in a single, mostly continuous row just beneath the ooplasm in all oocytes. Microvilli were well preserved after IVM. Vacuoles were only occasionally found in all oocytes and, if present, they were frequently associated with lysosomes. Mitochondria-smooth endoplasmic reticulum (M-SER) aggregates and mitochondria-vesicles (MV) complexes were commonly found in in vivo matured oocytes. However, large MV complexes partially replaced M-SER aggregates in IVM oocytes.

Autori: Giovanni Coticchio, Mariabeatrice Dal Canto, Rubens Fadini, Mario Mignini Renzini, Maria Cristina Guglielmo, Selenia Miglietta, Maria Grazia Palmerini, Guido Macchiarelli, Stefania Annarita Nottola