Inhaled nitric oxide decreases hyperoxia-induced surfactant abnormality in preterm rabbits.

Abstract

Inhaled nitric oxide (iNO) is a specific pulmonary vasodilator. By serving as a pro-oxidant or antioxidant, iNO may influence other pulmonary functions as well. This study was designed to test the hypothesis that iNO affects the alveolar lining after premature birth. Preterm rabbits (gestation 29 d, term 31 d) were nose-only exposed NO (14 ppm) and 98% O2, for 20 h. The others were exposed to either 98% O2 or air. In another experiment, premature rabbits were exposed to either NO in air or to air. After the exposure, bronchoalveolar lavage (BAL) was performed and the surfactant aggregates were isolated. The surfactant components and surface activity were analyzed. In total, 144 animals were studied. There were no significant differences in the number, distribution, or respiratory burst activity of cells recovered by BAL. Neither brief hyperoxia nor iNO increased plasma-derived proteins in BAL. Exposure to O2 decreased large surfactant aggregates, surface activity, and the content of surfactant protein B in BAL, whereas iNO prevented completely or partially these effects of acute hyperoxia on surfactant. Hyperoxia increased the content of malondialdehyde and decreased glutathione in epithelial lining fluid. iNO decreased malondialdehyde (p < 0.05) and tended to increase glutathione (p = 0.06) in animals breathing O2. Nitrotyrosine was not detectable in BAL, and NO2 was low in the breathing area. In room air, iNO had no significant effect on surfactant. According to the present results, a brief period of hyperoxia causes an oxidant stress and decreases the surface activity of alveolar surfactant in premature rabbits. In contrast, a low dosage of iNO decreased or prevented the O2-induced detrimental effects on alveolar surfactant and alleviated the oxidant stress.

• Authors: A Issa, U Lappalainen, M Kleinman, K Bry, M Hallman
• Journal: Pediatric research (Pediatr Res) Vol. 45 Issue 2 Pg. 247-54 (Feb 1999) ISSN: 0031-3998 [Print] United States
• PMID: 10022598 (Publication Type: Journal Article)

Chemical References

• Pulmonary Surfactants
• Nitric Oxide
• Glutathione

Topics

• Administration, Inhalation
• Analysis of Variance
• Animals
• Animals, Newborn
• Bronchoalveolar Lavage
• Bronchoalveolar Lavage Fluid (chemistry)
• Gestational Age
• Glutathione (metabolism)
• Hyperoxia (physiopathology)
• Macrophages, Alveolar (drug effects, physiology)
• Nitric Oxide (administration & dosage, pharmacology)
• Pulmonary Alveoli (drug effects, metabolism)
• Pulmonary Surfactants (metabolism)
• Rabbits
• Reference Values
• Respiratory Burst