Antagonists of embryo-derived platelet-activating factor act by inhibiting the ability of the mouse embryo to implant.
This study utilized the transfer of preimplantation embryos to pseudo-pregnant mice to determine whether PAF-antagonists act primarily on the maternal or embryonic components of implantation. The first experiment used reciprocal embryo transfers, in which blastocysts from mice treated with PAF antagonist (SRI 63-441) or saline (controls), from Days 1 to 4 of pregnancy, were transferred to Day-3 pseudo-pregnant recipients which were also treated with SRI 63-441 or saline on Days 1-4 of pregnancy. The antagonist (40 micrograms) was administered at 16:00 h on Day 1 and at 09:00 h on Days 2-4 of pregnancy. The percentage of the transferred embryos which implanted was determined on Day 8 of pregnancy. Treatment of the recipient or the donor female with SRI 63-441 resulted in a reduction in implantation rate, from a control level of 45% to 33.8% or 34.7% (P less than 0.0002, P less than 0.007) respectively. These results suggest that the PAF antagonist affected implantation at the embryonic and maternal levels. However, when the blastocysts were transferred to Day-4 pseudopregnant recipients, treatment of the donor female had a dramatic effect on the implantation rate, resulting in a reduction of 64% (from 40% to 14.3%, P less than 0.04), while treatment of the recipient female had no significant effect. In this later experiment the transferred embryos were exposed to the recipient uterine environment for a shorter period before implantation. These results suggest that PAF antagonists affected implantation at the embryonic level and did not adversely affect maternal physiology.(ABSTRACT TRUNCATED AT 250 WORDS)
Human Reproduction Unit, Royal North Shore Hospital of Sydney, St. Leonards, NSW, Australia.
N R
NR
Spinks
J P
JP
Ryan
C
C
O'Neill
D000818:Animals; D001381:Azepines / Q000494:pharmacology; D001755:Blastocyst / Q000187:drug effects*; D003656:Decidua / Q000187:drug effects; D010064:Embryo Implantation / Q000187:drug effects*; D004624:Embryo Transfer; D011464:Epoprostenol / Q000494:pharmacology; D005260:Female; D016285:Iloprost; D051379:Mice; D008815:Mice, Inbred Strains; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors*; D011247:Pregnancy; D011806:Quinolinium Compounds / Q000494:pharmacology; D014227:Triazines / Q000494:pharmacology; D014230:Triazoles; D014327:Trophoblasts / Q000187:drug effects
D001381:Azepines; D010972:Platelet Activating Factor; D011806:Quinolinium Compounds; D014227:Triazines; D014230:Triazoles; C050531:SRI 63-441; C052518:WEB 2086; D011464:Epoprostenol; D016285:Iloprost