Tracheal ligation and mechanical ventilation do not improve the antioxidant enzyme status in the lamb model of congenital diaphragmatic hernia.
OBJECTIVE
The antioxidant enzyme (AOE) system is the primary intracellular defense system of the lung against oxygen toxicity. The authors recently demonstrated depressed levels of catalase, glutathione peroxidase, and superoxide dismutase in congenital diaphragmatic hernia (CDH) lambs compared with controls. The aim of this study was to determine whether tracheal ligation (TL) or mechanical ventilation (recently shown to stimulate growth and surfactant metabolism, respectively) could induce an elevation in AOE activity.


METHODS
Four nonventilated lambs with surgically created CDH and TL and five CDH lambs ventilated for 4 hours were studied. Lung tissue was analyzed for AOE and the results compared with untreated CDH lambs.


RESULTS
Both ventilation and TL failed to elevate AOE activity above that of untreated CDH lambs.


CONCLUSIONS
The data provide further evidence that TL does not improve lung metabolism or maturation. Mechanical ventilation, which often involves high oxygen delivery, is a necessary and often beneficial therapeutic modality. In the CDH neonate compromised not only by low baseline levels of the AOE, but also by an inability to induce enzyme synthesis in response to hyperoxia, mechanical ventilation may, by causing lung injury, be contributing to the high morbidity and mortality rate associated with CDH.
Buffalo Institute of Fetal Therapy, Children's Hospital of Buffalo, Department of Pediatric Surgery, State University of New York at Buffalo, School of Medicine and Biomedical Sciences, 14222, USA.
P
P
Kapur
B A
BA
Holm
M S
MS
Irish
A
A
Patel
P L
PL
Glick
D000818:Animals; D000831:Animals, Newborn; D002374:Catalase / Q000378:metabolism; D005260:Female; D005333:Fetus; D005979:Glutathione Peroxidase / Q000378:metabolism; D006548:Hernia, Diaphragmatic / Q000503:physiopathology*; D065630:Hernias, Diaphragmatic, Congenital; D006801:Humans; D007231:Infant, Newborn; D008026:Ligation; D008168:Lung / Q000201:enzymology* / Q000378:metabolism; D011247:Pregnancy; D012121:Respiration, Artificial; D012756:Sheep; D013482:Superoxide Dismutase / Q000378:metabolism; D014132:Trachea / Q000601:surgery*
D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase