Regulation of preimplantation development of bovine embryos by interleukin-1beta.
Experiments were performed to determine the actions of recombinant bovine interleukin-1beta (IL-1beta) on the growth of preimplantation embryos. In the first series of studies, IL-1beta was added at 8-10 h after insemination, and the percentage of oocytes developing to the blastocyst stage was evaluated. IL-1beta increased development to the blastocyst stage when embryos were cultured at high density ( approximately 25-30 embryos/drop) but decreased or had no effect on development when cultured at low density ( approximately 10 embryos/drop). Thus, the positive effect of IL-1beta depends upon some other embryo-derived product. The effect of IL-1beta on embryonic development was maintained in completely denuded embryos, indicating that cumulus cells do not mediate the actions of IL-1beta. Maximum development of embryos cultured at approximately 25-30/drop occurred at 0.1-1 ng/ml; 10 ng/ml was less effective. Addition of IL-1beta to groups of approximately 25-30 embryos/drop at 8-10 h after insemination also increased embryo cell number at Day 5 postinsemination by increasing the proportion of embryos that reached the 9- to 16-cell stage. However, IL-1beta had no effect on the proportion of blastocysts when added at Day 5 postinsemination. Thus, IL-1beta probably acts to increase blastocyst numbers by exerting actions on embryo growth before Day 5. In contrast to its effect on embryos, addition of IL-1beta during oocyte maturation did not affect cumulus expansion, cleavage rate of oocytes, or subsequent development to the blastocyst stage. In conclusion, IL-1beta can modulate growth of bovine embryos at early stages of development in a manner dependent upon embryo density.
Paula-Lopes
F F
FF
a Department of Dairy&Poultry Sciences, University of Florida, Gainesville, Florida 32611-0920, USA.
de Moraes
A A
AA
Edwards
J L
JL
Justice
J E
JE
Hansen
P J
PJ
D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002417:Cattle / Q000196:embryology*; D046508:Culture Techniques; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro; D007375:Interleukin-1 / Q000008:administration & dosage / Q000494:pharmacology*; D009865:Oocytes / Q000502:physiology; D011247:Pregnancy; D011994:Recombinant Proteins / Q000494:pharmacology
D007375:Interleukin-1; D011994:Recombinant Proteins