Embryonic implantation in mice is blocked by interleukin-1 receptor antagonist.
We have investigated the relevance of interleukin-1 receptor type I (IL-1R tI) in the implantation process in vivo in a murine model. Indirect immunofluorescence experiments demonstrate that IL-1R tI is located in mouse endometrial lumenal epithelium with increased intensity in the periimplantation period, whereas IL-1 beta staining is located in the mouse placenta. PMSG/human CG (hCG)-stimulated and mated 12-week-old B6C3F-1 female mice were randomly allocated to three groups: A, control noninjected; B, buffer-injected animals; and C, animals injected ip with 20 micrograms recombinant human IL-1 receptor antagonist (rhIL-1ra) every 12 h beginning on pregnancy day 3. Injections were continued until day 9, and animals were killed 12 h after the last injection. Pregnancy rates in the three groups were: noninjected, 58.8% (10 of 17); buffer-injected, 73.7% (14 of 19); rhIL-1ra-injected, 6.7% (1 of 15), P = 0.0001155, Fisher exact test. To rule out the possibility that pregnancy failure was due to an embryotoxic effect of rhIL-1ra, 2-cell mouse embryos (n = 276) were flushed from the same group of animals used for in vivo experiments and cultured with increasing concentrations of rhIL-1ra: 0 microgram/ml (n = 91), 1 microgram/ml (n = 36), 50 micrograms/ml (n = 36), 100 micrograms/ml (n = 52), and 200 micrograms/ml (n = 61) rhIL-1ra. The percentages of 2-cell mouse embryos reaching the blastocyst stage after 72 h in culture were 85.7%, 91.6%, 94.4%, 96%, and 85.2%, respectively. We further cultured these blastocysts for 5 days on fibronectin-coated plates with or without 200 micrograms/ml rhIL-1ra. In both groups, hatching, attachment to fibronectin, outgrowth, and migration were documented to be similar. Furthermore, our longitudinal morphological study of embryonic implantation in control and rhIL-1ra-injected mice shows that the blockade of IL-1R tI interferes with the attachment of mouse blastocysts to maternal endometrium in vivo. In summary, we demonstrate that blockade of maternal endometrial IL-1R tI with IL-1ra prevents implantation in the mouse by interfering with embryonic attachment, without adverse effects on blastocyst formation, hatching, fibronectin attachment, outgrowth, and migration in vitro.
Simón
C
C
Department of Gynecology and Obstetrics, Stanford University Medical Center, California 94305.
Frances
A
A
Piquette
G N
GN
el Danasouri
I
I
Zurawski
G
G
Dang
W
W
Polan
M L
ML
D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D010064:Embryo Implantation / Q000187:drug effects* / Q000502:physiology; D004717:Endometrium / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D005260:Female; D005455:Fluorescent Antibody Technique; D006064:Gonadotropins, Equine / Q000494:pharmacology; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009924:Organ Culture Techniques; D010920:Placenta / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011247:Pregnancy; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D011994:Recombinant Proteins / Q000494:pharmacology; D012795:Sialoglycoproteins / Q000494:pharmacology*
D006063:Chorionic Gonadotropin; D006064:Gonadotropins, Equine; C507763:IL1RN protein, human; C507764:Il1rn protein, mouse; D053590:Interleukin 1 Receptor Antagonist Protein; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins; D012795:Sialoglycoproteins