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

OBJECTIVE: To determine whether intra-uterine infusion of interleukin-10 pr events preterm delivery in rats treated with endotoxin. METHODS: Pregnant rats under-vent implantation of uterine catheters and wer e randomly assigned to receive intrauterine infusion of either normal salin e, 50 mug lipopolysaccharide endotoxin, or 50 mug lipopolysaccharide with 5 00 ng interleukin-10 administered either concurrently or 24 hours later. Th e interval from infusion to delivery for each group was recorded, along wit h the number of live born pups and their birth weight. We calculated that t o 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 interv al to delivery (P < .05), live birth rate (P < .05), and pup weight (P < .0 01) were reduced compared with the saline-infused controls. In contrast, fe males 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 bi rth weight compared with the controls. CONCLUSION: Animals treated with both lipopolysaccharide and interleukin-10 , administered concurrently or 24 hours after the endotoxin challenge, deli vered normal weight pups at term with a similar litter size as the saline-i nfused controls. Interleukin-10 appears to be effective in preventing endot oxin-induced preterm. birth and fetal wastage in pregnant rats. (C) 2001 by the American College of Obstetricians and Gynecologists.