Umbilical Cord Arterial Concentrations of Isoprostane(8-iso-PGF2alpha) in Newborn Infants

PURPOSE: We measured the umbilical cord arterial concentrations of isoprostane(8-iso-PGF2alpha) and intended to decide whether the umbilical cord arterial concentrations of isoprostane could be used as a useful parameter for lipid peroxidation in newborn infants. METHODS: The isoprostane and malondialdehyde(MDA) concentrations of the umbilical cord were measured by enzyme immunoassay and TBARS(thiobarbituric acid reactive substance) assay in 33 preterm and 28 term infants, respectively. The concentrations of isoprostane and MDA were compared between preterm infants and term infants, and were analysed for association with perinatal risk factors and neonatal complications. RESULTS: Umbilical cord arterial concentrations of isoprostane were 704.7+/-635.6 pg/mL and 421.9+/-306.5 pg/mL in preterm and term infants, respectively. Umbilical cord arterial concentrations of MDA were 44.0+/-22.9 micrometer/L and 26.2+/-10.7 micrometer/L in preterm and term infants, respectively. Umbilical cord arterial concentrations of isoprostane and MDA in preterm infants were significantly higher than those in term infants(P<0.05). The umbilical cord arterial concentrations of isoprostane were significantly associated with perinatal risk factors such as fetal distress, oligohydramnios, and breech delivery in preterm infants and pregnancy-induced hypertension in term infants(P<0.05). CONCLUSION: Umbilical cord arterial concentrations of isoprostane in preterm infants were higher than those in term infants, and those are significantly associated with some perinatal risk factors.

Changes in the Levels of Eicosanoids and Isoprostane (8-iso-PGF2alpha) in the Newborn Rat Brain after Hypoxic-Ischemic Injury

PURPOSE: The changes in the levels of eicosanoids and isoprostane (8-iso-PGF2alpha) were investigated in brain tissue of 7 day-old rats after hypoxic-ischemic (HI) injury. METHODS: The 7 day-old newborn rats underwent right unilateral common carotid artery ligation followed by exposure to hypoxia with 8% oxygen for 150 minutes. There after, the pups were decapitated during reoxygenation 21% period of 0, 1, 6, 24, and 72 hours and their cerebral hemisheres were dissected through sagittal plane. Ipsilateral and contralateral cerebral hemesheres to common carotid artery ligation were used to determine the water content for estimation of severity of brain edema (n=5) and to measure the levels of eicosanoid and isoprostane (n=7). The levels of 6-keto-PGF1alpha, TXB2, and PGE2 were measured by RP-HPLC (reversed-phase high-performance liquid chromatography) and the levels of isoprostane (8-iso-PGF2alpha) were measured by enzyme immunoassay. The changes of eicosanoid and isoprostane levels during reoxygenation period were observed and comparisons between ipsilateral and contralateral hemispheres were done. RESULTS: The edema of ipsilateral cerebral hemesheres to common carotid artery ligation was more severe than that of contralateral cerebral hemisheres (P<0.05). The levels of 6-keto-PGF1alpha, TXB2, and PGE2 were found to increase during the early period of reoxygenation after HI insult, peak at 1 hour, and then decrease to the control levels at 72 hour (P<0.05). But, the levels of 8-iso-PGF2alpha did not significantly increase during the period of reoxygenation. The levels of 6-keto-PGF1alpha, TXB2, and PGE2 of ipsilateral hemispheres had a tendency to be higher than those of contralateral hemispheres during the initial 6 hour reoxygenation period, but the levels of 8-iso-PGF2alpha of ipsilateral hemispheres were significantly higher than those of contralateral hemispheres during the relatively later reoxygenation period (P<0.05). CONCLUSION: Reoxygenation after hypoxic-ischemic injury increased the levels of 6-keto-PGF1alpha, TXB2, and PGE2 in 7 day-old rat brain during the early period of reoxygenation, but the levels of isoprostane (8-iso-PGF2alpha) were not significantly increased during the reoxygenation period after HI injury.