Interleukin-10 administration and bacterial endotoxin-induced preterm birth in a rat model

OBJECTIVE: To determine whether intra-uterine infusion of interleukin-10 prevents preterm delivery in rats treated with endotoxin. METHODS: Pregnant rats under-vent implantation of uterine catheters and were randomly assigned to receive intrauterine infusion of either normal saline, 50 mug lipopolysaccharide endotoxin, or 50 mug lipopolysaccharide with 500 ng interleukin-10 administered either concurrently or 24 hours later. The interval from infusion to delivery for each group was recorded, along with the number of live born pups and their birth weight. We calculated that to obtain a power of 80%, assuming a 24-hour difference in the treatment to delivery times between the test and control subjects, at least six animals would be needed in each group. RESULTS. In females receiving lipopolysaccharide (50 mug) alone, the interval to delivery (P < .05), live birth rate (P < .05), and pup weight (P < .001) were reduced compared with the saline-infused controls. In contrast, females receiving interleukin-10 at the time of the endotoxin challenge or 24 hours after delivered at term with no difference in litter size or live birth weight compared with the controls. CONCLUSION: Animals treated with both lipopolysaccharide and interleukin-10, administered concurrently or 24 hours after the endotoxin challenge, delivered normal weight pups at term with a similar litter size as the saline-infused controls. Interleukin-10 appears to be effective in preventing endotoxin-induced preterm. birth and fetal wastage in pregnant rats. (C) 2001 by the American College of Obstetricians and Gynecologists.