Treatment with the interleukin-I receptor antagonist and soluble tumor necrosis factor receptor Fc fusion protein does not prevent endotoxin-induced preterm parturition in mice.
OBJECTIVE
To determine whether the administration of anticytokine agents, the interleukin-1 receptor antagonist (IL-1ra) and a soluble tumor necrosis factor receptor Fc fusion protein (sTNFR-Fc), prevents endotoxin-induced preterm delivery in mice.


METHODS
C3H/HeN pregnant mice at 15 days of gestation (70% gestation) were randomized to receive phosphate-buffered saline (PBS) or lipopolysaccharide (LPS) (50 micrograms/mouse) intraperitoneally (i.p.). Randomly selected PBS- or LPS-treated mice were additionally treated intravenously (i.v.), i.p., or subcutaneously (s.c.) every 3 hours with IL-1ra (1-50 mg) or every 12 hours with sTNFR-Fc (200-400 micrograms) beginning 1 hour before LPS injection. Animals were observed for vaginal bleeding and preterm delivery.


RESULTS
Mice treated i.p. with 50 micrograms LPS (n = 13) had a shorter injection-to-delivery interval than mice treated similarly with PBS (n = 19) (median 13.5 hours, range 10-105 versus median 86.8 hours, range 53-120, respectively; P < .001). Saline-treated mice given 10 mg IL-1ra every 3 hours i.p. (n = 3) or 200 micrograms sTNFR-Fc every 12 hours i.v. (n = 4) had similar injection-to-delivery intervals as PBS-treated control mice (median 70 hours, range 70-76 versus median 58 hours, range 50-120, respectively). Similarly, LPS-treated mice given PBS every 3 hours (n = 20) had injection-to-delivery intervals comparable to LPS-treated mice (n = 13) (median 15.5 hours, range 9.8-92 versus median 13.5 hours, range 10-105, respectively). Lipopolysaccharide-treated mice given i.p. injections of 1 (n = 4), 10 (n = 31), or 50 (n = 15) mg of IL-1ra every 3 hours did not have longer injection-to-delivery intervals compared with LPS-treated mice (n = 13) (medians 11.6, 15, 14.5 and 13.5 hours; ranges 10.8-12, 8-95, 11-92, and 10-105, respectively). Lipopolysaccharide-treated mice given i.v. injections of 200 (n = 4) or 400 (n = 9) micrograms sTNFR-Fc every 12 hours did not have longer injection-to-delivery intervals compared with LPS-treated mice (n = 8) (medians 23.3, 22.5, and 21.9 hours; ranges 14.8-33, 15-95.5, and 15.5-44, respectively). The median injection-to-delivery interval of LPS-treated mice given both IL-1ra (10 mg) every 3 hours i.p. and sTNFR-Fc (200 micrograms) every 12 hours i.v. (n = 5) was not different from that of LPS-treated mice (median 26 hours, range 24.5-72 versus median 13.5 hours, range 10-105, respectively; P > .05).


CONCLUSIONS
The anticytokine agents IL-1ra and sTNFR-Fc did not prevent preterm delivery or prolong pregnancy in endotoxin-induced preterm labor in mice.
Fidel
P L
PL
Department of Obstetrics and Gyncology, Wayne State University School of Medicine, Detroit, Michigan, USA.
Romero
R
R
Cutright
J
J
Wolf
N
N
Gomez
R
R
Araneda
H
H
Ramirez
M
M
Yoon
B H
BH
D000818:Animals; D005260:Female; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D053590:Interleukin 1 Receptor Antagonist Protein; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D018123:Receptors, Interleukin / Q000037:antagonists & inhibitors*; D018124:Receptors, Tumor Necrosis Factor; D011993:Recombinant Fusion Proteins / Q000627:therapeutic use*; D011994:Recombinant Proteins / Q000627:therapeutic use; D012795:Sialoglycoproteins / Q000627:therapeutic use*
C507764:Il1rn protein, mouse; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D053590:Interleukin 1 Receptor Antagonist Protein; D018123:Receptors, Interleukin; D018124:Receptors, Tumor Necrosis Factor; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D012795:Sialoglycoproteins