Hayashibe H, Asayama K, Dobashi K, Kato K
Department of Pediatrics, Yamanashi Medical College, Japan.
Pediatr Res. 1990 May;27(5):472-5. doi: 10.1203/00006450-199005000-00011.
The immaturity of antioxidant capacity in the lung in preterm newborn infants is postulated to contribute to the development of hyperoxic lung injury. Antioxidant enzymes in fetal lung, comprised of copper-zinc (cytosolic) and manganese (mitochondrial) superoxide dismutases, glutathione peroxidase, and catalase, have been reported to increase during the late gestational period. To determine whether such maturation of antioxidant capacity occurs in other tissues, we have evaluated the development of these four enzymes from d 18 to 22 of gestation in rat lung, kidney, and heart. To resolve the confusion in the reported levels of lung superoxide dismutases, the two isoenzymes were assayed separately by specific RIA. The growth of the kidney exceeded that of the whole body during this period, while the growth of the lung and heart did not. The concentrations of the four antioxidant enzymes in lung and kidney increased in a stepwise manner during this period, and the magnitude of the change for each enzyme was greater in the kidney than in the lung. On the other hand, the only significant change in the concentrations of heart antioxidant enzymes observed was a mild increase in the glutathione peroxidase concentration from d 20 to 22. These results suggest that the prenatal maturation of antioxidant capacity occurs earlier in the heart and later in the kidney than in the lung, and that the immaturity of antioxidant capacity could make the fetal rat kidney vulnerable to free radical-mediated injury.
早产儿肺中抗氧化能力的不成熟被认为是导致高氧性肺损伤的原因之一。据报道，胎儿肺中的抗氧化酶，包括铜锌（胞质）和锰（线粒体）超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶，在妊娠后期会增加。为了确定这种抗氧化能力的成熟是否也发生在其他组织中，我们评估了妊娠第18至22天大鼠肺、肾和心脏中这四种酶的发育情况。为了解决所报道的肺超氧化物歧化酶水平的混乱问题，通过特异性放射免疫分析法分别测定了这两种同工酶。在此期间，肾脏的生长超过了全身的生长，而肺和心脏的生长则没有。在此期间，肺和肾中四种抗氧化酶的浓度呈逐步增加，且每种酶在肾脏中的变化幅度大于肺。另一方面，观察到心脏抗氧化酶浓度的唯一显著变化是从第20天到第22天谷胱甘肽过氧化物酶浓度略有增加。这些结果表明，抗氧化能力的产前成熟在心脏中比在肺中更早发生，在肾脏中比在肺中更晚发生，并且抗氧化能力的不成熟可能使胎鼠肾脏易受自由基介导的损伤。
