Molecular characteristics of oocytes and somatic cells of follicles at different sizes that influence in vitro oocyte maturation and embryo production

During the last 10 to 15 yr, in vitro research to predict antral follicle growth and oocyte maturation has delivered interesting advances in the knowledge of processes regulating follicle growth and developmental competence of oocytes. This review discusses the contribution of cumulus and mural granulosa cells in the process of oocyte maturation and cumulus expansion in cumulus-oocyte complexes (COCs) from follicles of different sizes and shows that differences in gene expression in oocytes, granulosa, and theca cells of small and large follicles impact the success of in vitro blastocyst development. In addition, the molecular mechanisms by which COC metabolism and antioxidant defense provide oocyte competence are highlighted. Furthermore, new insights and perspectives on molecular and cellular regulation of in vitro oocyte maturation are emphasized. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

In vitro research has made significant advances in predicting antral follicle growth and oocyte maturation, with a focus on the roles of cumulus and mural granulosa cells. Differences in gene expression in small and large follicles impact the success of in vitro blastocyst development, while molecular mechanisms related to COC metabolism and antioxidant defense are highlighted as crucial for oocyte competence. New insights and perspectives on the molecular and cellular regulation of in vitro oocyte maturation are emphasized.