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Effect of food restriction on hyperoxia-induced lung injury in preterm guinea pig
1Department of Human Nutrition, University of Southampton, United Kingdom.
Insights
Undernutrition increases mortality in preterm infants exposed to high oxygen. This study found starved preterm guinea pigs had higher mortality in 95% oxygen, but lung injury and antioxidant defenses were unaffected.
Area of Science:
- Neonatal Physiology
- Respiratory Medicine
- Pediatric Critical Care
Background:
- Premature infants often experience undernutrition and require oxygen therapy.
- Hyperoxia can cause lung injury, and undernutrition may worsen this effect.
Purpose of the Study:
- To investigate if food restriction exacerbates hyperoxia-induced lung injury in preterm guinea pigs.
- To assess the impact of undernutrition on mortality and pulmonary antioxidant defenses under hyperoxic conditions in preterm neonates.
Main Methods:
- Preterm guinea pig pups were subjected to 72 hours of food restriction.
- Pups were then exposed to either 95% oxygen or room air (21% oxygen).
- Mortality rates, pulmonary microvascular leakage, and lung antioxidant enzyme activities were measured.
Main Results:
- Food restriction significantly increased mortality in pups exposed to 95% oxygen (8/18) but not in those exposed to room air (0/10).
- Hyperoxia did not increase pulmonary microvascular leakage in starved pups.
- Pulmonary antioxidant enzyme activities and glutathione concentrations were largely unchanged by starvation or hyperoxia.
Conclusions:
- Undernutrition increases susceptibility to lethal hyperoxia in preterm neonates.
- This increased susceptibility is not explained by impaired pulmonary antioxidant defenses or increased lung injury.
- Findings highlight the importance of nutritional support in managing preterm infants receiving oxygen therapy.
Abstract:
Undernutrition may exacerbate hyperoxia-induced lung injury, a finding that may be of significance in the early clinical management of the premature human infant. Addressing this specific problem, we found that 72 h of food restriction in guinea pig pups delivered 3 days preterm increased mortality rates among pups exposed to 95% oxygen (8/18) and yet had no effect on 21% oxygen (air)-exposed pups (0/10). Reduced tolerance of hyperoxic conditions was not, however, associated with increased lung injury, assessed as pulmonary microvascular leakage. Pulmonary antioxidant enzyme activities [Cu,Zn superoxide dismutase (SOD), Mn SOD, glutathione peroxidase, and catalase] were unaltered by starvation or hyperoxia. Lung glutathione concentration was slightly decreased after food restriction, whereas hyperoxic exposure did not change either lung or bronchoalveolar lavage fluid glutathione concentrations or lung antioxidant enzyme activities. Increased susceptibility to the lethal effects of oxygen in the starved preterm guinea pig pup could not be attributed to a deficiency of pulmonary antioxidant defenses.