Premium
Factors affecting the in vitro action of cumulus cells on the maturing mouse oocytes
Author(s) -
Ge Li,
Han Dong,
Lan GuoCheng,
Zhou Ping,
Liu Yong,
Zhang Xia,
Sui HongShu,
Tan JingHe
Publication year - 2008
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20753
Subject(s) - oocyte , biology , germinal vesicle , microbiology and biotechnology , in vitro maturation , blastocyst , somatic cell , follicular phase , gamete , andrology , embryo , embryogenesis , endocrinology , genetics , sperm , medicine , gene
The removal of cumulus cells (CCs) from oocytes at the germinal vesicle (GV) stage still represents a major limitation in such embryo techniques as GV transfer, somatic cell haploidization, and oocyte cryopreservation. However, no efficient in vitro maturation (IVM) system for CC‐denuded oocytes (DOs) has been established in mammalian species. Although follicular cells are considered to play an important role in oocyte maturation, the specific role and mechanisms of action of different cell types are poorly understood. Reports on whether junctional association between CCs and the oocyte is essential for the beneficial effect of CC co‐culture on oocyte maturation are in conflict. Our objective was to try to address these issues using the mouse oocyte model. The results indicated that while co‐culture with the CC monolayer could only partially restore the developmental potential of DOs without corona cells, it restored the competence of corona‐enclosed DOs completely. Culture in medium conditioned with CC monolayer also promoted maturation of DOs. However, co‐culture with the monolayer of mural granulosa cells had no effect. The efficiency of CC co‐culture was affected by various factors such as density and age of the CCs, the presence of gonadotropin in the maturation medium and the duration for in vivo (IVO) gonadotropin priming. It is concluded that mouse CCs produce a diffusible factor(s) that support DO maturation in a CC‐oocyte junctional communication dependent manner. The data will contribute to our understanding the mechanisms by which CCs promote oocyte maturation and to the establishment of an efficient DO IVM system. Mol. Reprod. Dev. 75: 136–142, 2008. © 2007 Wiley‐Liss, Inc.