Influences of epidermal growth factor and insulin-like growth factor-I on bovine blastocyst development in vitro.
Experiments were carried out to investigate putative beneficial effects of adding epidermal growth factor (EGF) or insulin-like growth factor-I (IGF-I) for bovine embryo culture in chemically defined media. Presumptive zygotes (18 h post-insemination) were randomly assigned to culture treatments. In experiment 1, treatments involved additions of recombinant human EGF to provide concentrations of 0 ng (control), 1, 5, and 25 ng/ml. No differences were seen in numbers of 4-cell stage embryos between groups. A concentration of 5 ng/ml EGF but not 1 or 25 ng/ml during embryo culture improved percentages of 4-cell stage embryos reaching blastocysts compared to the control (P<0.05). Numbers of inner cell mass (ICM) cells and trophoblast cells of day 8 blastocysts were similar for the control and 5 ng/ml EGF-treated groups. In experiment 2, culture with recombinant human IGF-I in concentrations of 0 ng (control), 2, 10, and 50 ng/ml resulted in no differences in numbers of 4-cell stage embryos between groups. When compared to controls, IGF-I treatments at 10 and 50 ng/ml improved proportions of 4-cell stage embryos that reached blastocysts (P<0.05). In experiment 3, numbers of ICM cells of day 8 blastocysts were significantly higher after being cultured with 50 ng/ml of IGF-I compared to those of the controls (P<0.05). No additive effect of combining EGF (5 ng/ml) and IGF-I (50 ng/ml) was seen when results were compared to those following supplementation of the media with either EGF or IGF-I alone. In conclusion, both EGF and IGF-I could independently enhance bovine preimplantational development in chemically defined media and IGF-I but not EGF may play a mitogenic role during early bovine development.
Sirisathien
S
S
Department of Physiology and Pharmacology, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602-7389, USA.
Hernandez-Fonseca
H J
HJ
Brackett
B G
BG
D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002417:Cattle / Q000196:embryology*; D003470:Culture Media; D046508:Culture Techniques; D004347:Drug Interactions; D047108:Embryonic Development; D005314:Embryonic and Fetal Development / Q000187:drug effects*; D004815:Epidermal Growth Factor / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000494:pharmacology*; D011247:Pregnancy; D011994:Recombinant Proteins / Q000494:pharmacology
D003470:Culture Media; D011994:Recombinant Proteins; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I