Bilirubin influence on oxidative lung damage and surfactant surface tension properties.
To study the hypothesis that hyperbilirubinemia might reduce in vivo oxidative lung damage while also diminishing lung surfactant surface tension properties during acute lung injury, we performed a randomized study in a rabbit model of acute lung injury. Twenty rabbits were randomized to receive bilirubin or saline intravenously. Acute lung injury was induced by lung lavages with saline. Lung tissue oxidation was evaluated by measuring total hydroperoxide (TH), advanced oxidation protein products (AOPP), and protein carbonyls (PC) in bronchial aspirate (BA) samples. Surface surfactant activity was studied in BA samples using a capillary surfactometer. Bilirubin BA concentration increased in bilirubin-treated rabbits, while it remained undetectable in controls. A similar increase in TH, AOPP, and PC bronchial aspirate concentrations was found in both the study and control groups, while surfactant surface activity was lower in the bilirubin than in the control group. We conclude that during hyperbilirubinemia, bilirubin enters the lung tissue, where it can be detected in BA fluid. Bilirubin is not effective as an antioxidant agent and exerts a detrimental effect on lung surfactant surface tension properties. These findings may have relevance to the management of premature neonates suffering from respiratory distress syndrome and hyperbilirubinemia.
Section of Neonatology, Department of Surgical and Medical Critical Care, University of Florence, Florence, Italy. cdani@unifi.it
Carlo
C
Dani
Elena
E
Martelli
Michele
M
Tronchin
Giuseppe
G
Buonocore
Mariangela
M
Longini
Alessandro
A
Di Filippo
Massimo
M
Giossi
Firmino F
FF
Rubaltelli
D000818:Animals; D001663:Bilirubin / Q000494:pharmacology*; D005260:Female; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects* / Q000502:physiology; D011663:Pulmonary Surfactants; D011897:Random Allocation; D012131:Respiratory Insufficiency / Q000503:physiopathology; D013500:Surface Tension
D011663:Pulmonary Surfactants; D001663:Bilirubin