Intra-amniotic interleukin-1 alpha treatment alters postnatal adaptation in premature lambs.

We measured the physiological and biochemical responses of preterm lambs to intra-amniotic injection of interleukin-1 alpha (IL-1 alpha). Singleton lamb fetuses at 126 days of gestation were randomized to receive 125 micrograms IL-1 alpha or vehicle control via ultrasound-guided intra-amniotic injection. Each lamb was delivered 48 h later by caesarian section and ventilated for 120 min. Relative to controls, IL-1 alpha-treated lambs had higher dynamic compliance, ventilatory efficiency indices, and saturated phosphatidylcholine levels (all p < 0.05). Umbilical cord plasma cortisol and catecholamine levels, white blood cells and differentials, cardiac output, regional blood flow, and kidney function did not differ between the groups. However, at 120 min after delivery, the cortisol levels for IL-1 alpha-treated animal were higher than for controls. Single intra-amniotic IL-1 alpha treatment increases surfactant pool size and improves dynamic compliance in the absence of an inflammatory response or differences in other indicators of fetal or newborn organ function.