Effects of prostaglandins and indomethacin on the cellular inflammatory response following surgical trauma in fetal rabbits.

This study has examined the effects of prostaglandins E2 and F2a (PGE2 and PGF2a) and indomethacin on cellular inflammation in fetal rabbits. Fetuses heal differently from adults: incisions heal with no scar or inflammation; excisional wounds exposed to amniotic fluid (AF) do not heal or become inflamed, and have high tissue levels of PGE2 and PGF2a; excisional wounds protected from AF do heal and become inflamed, and have low tissue PG levels. The authors inserted slow-release pellets [control, PGE2 (10 micrograms), PGF2a (10 micrograms), indomethacin (10 micrograms)] into subcutaneous pockets in fetal rabbits on day 25 of gestation (one per fetus). Pellets were also placed in subcutaneous pockets in the does. Fetuses and doe tissues were recovered 72 h after surgery. Control pellets in fetuses had a slight inflammatory response, with some cells present. Fetal PGE2 pellets had a layer 5-10 cells thick surrounding the pellet, and fetal PGF2a pellets had a 10-15-cell layer. Fetal indomethacin pellets had no response, with no inflammatory cells present. All pellets placed in does elicited a slight cellular inflammatory response, equal to that seen with control pellet in fetuses. These results show that PGE2 and PGF2a are potent in-vivo promoters of cellular inflammation in fetal rabbits, but not in adult rabbits. Indomethacin suppresses the foreign-body response in fetal rabbits, but not in adult rabbits.