Epidermal growth factor effects on marmoset monkey (Callithrix jacchus) oocyte in vitro maturation, IVF and embryo development are altered by gonadotrophin concentration during oocyte maturation.
BACKGROUND
This is the first study of the effect of epidermal growth factor (EGF) on marmoset monkey oocytes matured in vitro.


METHODS
We have evaluated the effects of 10 ng/ml EGF in combination with 1 or 10 IU/ml of gonadotrophins (FSH/hCG 1:1 ratio) during in vitro maturation (IVM) of marmoset oocytes. Immature cumulus-oocyte complexes (COCs) were retrieved from ovarian antral follicles of unprimed monkeys. COCs from six animals (n= 268) used in this study were randomly distributed among four experimental groups: (A) 1 FSH +1 hCG; (B) 10 FSH +10 hCG; (C) 1 FSH +1 hCG + EGF; and (D) 10 FSH +10 hCG + EGF (where 1 and 10 are concentrations, IU/ml). After IVM, oocytes were fertilized in vitro and embryos were allowed to progress up to 87-88 h.


RESULTS
the highest rate of total and radial cumulus expansion was observed in Group A, with the lowest in Group B (P < 0.05). Neither maturation nor fertilization rate were affected by gonadotrophin concentration or presence of EGF. Addition of EGF increased degeneration and decreased first cleavage rate, which was significantly lower in Group C than Group A (P < 0.005). Interestingly, in the EGF groups some embryos cleaved faster than without EGF.


CONCLUSIONS
The effects of EGF are highly dependent on concentration of gonadotrophins present in IVM medium. EGF has a negative effect on oocytes in the presence of low gonadotrophins, but contrastingly partially protects oocytes from the negative effects of high gonadotrophins. We propose that these observed negative effects of EGF may suggest use of an inappropriate dose of growth factor.
Tkachenko
O Y
OY
Laboratory of Biomedical Reproduction, German Primate Centre, Goettingen, Germany.
Delimitreva
S
S
Isachenko
E
E
Valle
R R
RR
Michelmann
H W
HW
Berenson
A
A
Nayudu
P L
PL
D000818:Animals; D002144:Callithrix; D018929:Cell Culture Techniques; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D002970:Cleavage Stage, Ovum / Q000187:drug effects; D003470:Culture Media; D046149:Embryo Culture Techniques; D004622:Embryo, Mammalian / Q000000981:diagnostic imaging / Q000187:drug effects; D047108:Embryonic Development / Q000187:drug effects*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D005306:Fertilization / Q000187:drug effects; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D012102:Reproductive Control Agents / Q000494:pharmacology*; D014463:Ultrasonography
D006063:Chorionic Gonadotropin; D003470:Culture Media; D012102:Reproductive Control Agents; D004815:Epidermal Growth Factor; D005640:Follicle Stimulating Hormone