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Prepubertal bovine oocyte: a negative model for studying oocyte developmental competence
H Khatir1, P Lonergan, C Carolan
1Station de Physiologie de la Reproduction, INRA, Nouzilly, France.
Molecular Reproduction and Development
|October 1, 1996
Summary
Cow and calf oocytes show similar protein profiles, but follicular fluid differs, impacting development. Epidermal growth factor (EGF) significantly improves prepubertal calf oocyte maturation and embryo development.
Area of Science:
- Reproductive Biology
- Oocyte Development
- Mammalian Reproduction
Background:
- Oocyte quality and developmental potential are critical for successful reproduction.
- Differences in oocyte maturation and developmental capacity between young and adult animals are not fully understood.
- Investigating protein profiles and the role of follicular fluid can reveal insights into oocyte maturation markers.
Purpose of the Study:
- To compare the developmental capacity and protein profiles of cow and calf oocytes.
- To assess the impact of epidermal growth factor (EGF) and fetal calf serum (FCS) on in vitro maturation (IVM) and subsequent embryo development of calf oocytes.
- To investigate the role of follicular fluid (FF) in oocyte maturation.
Main Methods:
- Comparative analysis of constitutive and neosynthetic protein profiles of cow and calf oocytes and follicular fluid.
- In vitro maturation (IVM) of prepubertal calf oocytes with and without EGF.
- Assessment of embryo development, including cleavage rates and blastocyst yields, with and without FCS supplementation.
- Immunofluorescence detection of EGF receptors (EGF-R) on cumulus-oocyte complexes (COCs).
Main Results:
- No significant differences in constitutive protein profiles between cow and calf oocytes; minor differences in neosynthesized proteins observed.
- Quantitative differences in constitutive protein profiles of follicular fluid (FF) between cow and calf ovaries.
- EGF significantly enhanced cumulus expansion, cleavage rates, and blastocyst yields of prepubertal calf oocytes during IVM.
- Fetal calf serum (FCS) had no significant effect on embryo development from calf oocytes.
Conclusions:
- Oocyte protein patterns alone do not fully explain developmental differences between cow and calf oocytes.
- Follicular fluid (FF) composition plays a crucial role in modulating oocyte developmental potential.
- EGF is a key factor for improving in vitro maturation and developmental capacity of prepubertal calf oocytes.