Cellular inflammation of fetal excisional wounds: effects of amniotic fluid exclusion.

The development of an cellular inflammatory response secondary to mechanical wounding has not been observed previously in the fetus. The effect of amniotic fluid exclusion on the inflammatory response in fetal rabbits subjected to full-thickness dorsal excisional wounds on day 25 of gestation (term = 31-32) was examined. The fetuses were either returned immediately to the uterus; a silicone cover was sutured over the wound; or a silicone cover with a centrally located hole was sutured over the wound. Seventy-two hours after wounding, uncovered wounds (19 live fetuses) exhibited only occasional inflammatory cells. Covered wounds (14 live fetuses) showed a pronounced cellular inflammatory response. Partially covered wounds (six live fetuses) showed a peripheral, intermediate response. The findings suggest that amniotic fluid contains factors inhibitory to inflammation, which the cover effectively excludes.