Intrauterine endotoxin infusion in rat pregnancy induces preterm delivery and increases placental prostaglandin F2alpha metabolite levels.
OBJECTIVE
This study was designed to examine the effects of intrauterine endotoxin (lipopolysaccharide) on rat pregnancy.


METHODS
Pregnant Sprague-Dawley rats (N = 26) were implanted with uterine catheters on day 15 or 16 of a 22-day gestation. Animals were randomly assigned to receive either lipopolysaccharide (25 or 50 microg) or sodium chloride solution (1 mL) on day 17 and then were either sacrificed on day 19 or observed until delivery. Placentas were harvested at the time of death, homogenates were prepared, and prostaglandin F(2)(alpha) metabolite levels were determined by means of radioimmunoassay. Data were analyzed by analysis of variance, Student-Newman-Keuls, and Mann-Whitney tests.


RESULTS
Lipopolysaccharide-treated groups (25 and 50 microg) displayed a shorter interval to delivery (mean +/- SE, 82 +/- 13 and 63 +/- 8 hours, respectively) than control animals (117 +/- 3 hours). Pups of lipopolysaccharide-treated (25 and 50 microg) female animals had lower live birth weights (4.92 +/- 0.01 and 5.12 +/- 0. 24 g, respectively) compared with control animals (6.04 +/- 0.07 g). Placental homogenates from lipopolysaccharide-treated female animals contained higher levels of prostaglandin F(2)(alpha) metabolite (1567 +/- 64 and 1475 +/- 59 pg/mL) than those from sodium chloride solution-infused control animals (804 +/- 68 pg/mL).


CONCLUSIONS
Bacterial products induce the preterm delivery of low-birth-weight pups in rats, possibly by increasing local prostaglandin biosynthesis.
Bennett
W A
WA
Departments of Obstetrics and Gynecology and Physiology, University of Mississippi Medical Center, Jackson, USA.
Terrone
D A
DA
Rinehart
B K
BK
Kassab
S
S
Martin
J N
JN
Granger
J P
JP
D000818:Animals; D001724:Birth Weight / Q000187:drug effects; D002404:Catheterization; D036861:Delivery, Obstetric; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000008:administration & dosage* / Q000494:pharmacology; D005260:Female; D020567:Fetal Weight / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D007752:Obstetric Labor, Premature / Q000139:chemically induced*; D009929:Organ Size / Q000187:drug effects; D010920:Placenta / Q000033:anatomy & histology / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014599:Uterus
D004731:Endotoxins; D008070:Lipopolysaccharides; C008228:15-keto-13,14-dihydroprostaglandin F2alpha; D015237:Dinoprost