Text Box: THE PLASMA ANTIOXIDANTS IN OXYGEN SUPPLEMENTION PRETERM INFANTS
Xia S W, Chang L W, Zhang X H, Liu H C
Department of Pediatrics, Tongji Hospital, Tongji Medical Collage, Huazhong University of Science and Technology, China

Objective: To assess oxidative stress responses in preterm infants treated with elevated concentrations of oxygen, and find susceptive and feasible blood markers.
Methods: Forty prematurely born infants (gestational age 31-36 weeks) and ten healthy full term infants were enrolled into the study. In the preterm infants group, those who required oxygen supplemention (FiO2>0.50) because of non-infection diseases were classified as group A. The twenty remaining premature infants required no specific support and were classified as group B. The full term infants were group C. All infants were treated according to hospital procedures at that time. Heparinized blood in group A was sampled in d 0 (before oxygen), d 3, d 7 if oxygen was needed. Blood was centrifuged (750g, 10min) with 15min after collection and the plasma stored at –20℃ until spectrophphotometric analysis of GSH, GPX, GST, MDA. The time and methods in group B and C were the same as group A.
Results: 1) GSH the plasma concentrations of GSH in group A were decreased significantly at d 3,7. At birth, prematurely born infants had lower peripheral venous plasma GSH concentrations than term babies (p<0.05). The concentrations in group B and C also show a decreasing tendency but there were no significance differences. 2) GST, GPX the activity of GST and GPX was also decreased significantly (p<0.05). At birth, the concentrations of GPX in term infants were higher than that in the preterm, but GST were contrary, and the decline of GST concentration is directly related to oxygen therapy.3: MDA the concentrations of MDA in group A were elevated during oxygen therapy.
Conclusion: Due to the deficient capacity of the lung, preterm infants are thought to be hypersusceptible to oxidative stress. Oxidative stress is likely to increase if hyperoxic treatment is given for respiratory distress in these infants, and this may be the main reason of hyperoxic lung demage.



2467