RESUMO
BACKGROUND: Preterm birth is associated with an increased oxidant burden which places these infants at a higher risk of injury. AIMS: This prospective study aimed to assess levels of antioxidants and a marker of oxidative stress in preterm neonates. OBJECTIVES: (i) To compare levels of anti-oxidants [vitamin A, vitamin E, catalase, total anti-oxidant status (TAS)] as well as malondialdehyde level (MDA) (a marker of lipid peroxidation) between preterm and full-term neonates; (ii) to determine changes in the values of measured vitamins at birth and at discharge among preterm neonates; and (iii) to compare levels of anti-oxidants with MDA levels in relation to complications of prematurity and outcome. METHODS: The study was undertaken in 100 preterm neonates and 100 full-term neonates as a control group. MDA was estimated by a thiobarbituric acid-reactive technique; TAS was determined using a Randox assay kit; catalase activity was measured spectrophotometrically and vitamin A and E levels were estimated by high performance liquid chromatography. RESULTS: The plasma levels of vitamin A, vitamin E, TAS and catalase were significantly lower in the preterm than in the full-term group (P < 0.01), and the plasma level of MDA was significantly higher in preterm than full-term neonates (P < 0.01). Vitamin A and E levels in preterm neonates were significantly higher at discharge than at birth (P < 0.01). Vitamin A, vitamin E and catalase levels at birth were significantly lower in patients who developed necrotizing enterocolitis or bronchopulmonary dysplasia than in those who did not. CONCLUSION: Preterm neonates are exposed to increased oxidant stress at birth and are susceptible to anti-oxidant deficiencies. A higher dose of enteral vitamin A supplementation in preterm neonates might reduce morbidity and improve outcome. Further studies are warranted to evaluate the appropriate dose of oral vitamin E supplementation for preterm neonates.
