Surfactant protein B corrects oxygen-induced pulmonary dysfunction in heterozygous surfactant protein B-deficient mice.
Surfactant protein B (SP-B) is a 79-amino acid hydrophobic surfactant protein that plays a critical role in postnatal lung function. Homozygous SP-B (-/-)-deficient mice die of respiratory failure at birth, associated with severe pulmonary dysfunction and atelectasis. Heterozygous SP-B (+/-)-deficient mice have 50% less SP-B protein, proprotein, and SP-B mRNA compared with control mice and are highly susceptible to oxygen-induced lung injury. In the current study, we tested whether the susceptibility of SP-B (+/-) mice to hyperoxia was restored by intratracheal administration of exogenous SP-B. After exposure to 95% oxygen for 3 d, opening pressures were increased and maximal lung volumes were significantly decreased in SP-B (+/-) mice compared with SP-B (+/+) mice. SP-B (+/-) mice were administered purified bovine SP-B (2%) with DL-alpha dipalmitoyl phosphatidylcholine (DPPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-rac-( -glycerol)] (POPG) phospholipids or DPPC and POPG phospholipids intratracheally and exposed to 95% oxygen. SP-B-treated SP-B (+/-) mice survived longer in 95% oxygen. Although decreased lung function in SP-B (+/-) mice exposed to oxygen was not altered by administration of DPPC and POPG, administration of lipids containing 2% purified bovine SP-B restored lung function when assessed after 3 d in oxygen. Abnormalities in pulmonary function in SP-B (+/-) mice after oxygen exposure were associated with increased alveolar capillary leak, which was corrected by administration of SP-B with DPPC and POPG. Likewise, histologic abnormalities caused by oxygen-induced lung injury were improved by administration of SP-B with DPPC and POPG. Administration of phospholipids with the active SP-B peptide was sufficient to restore pulmonary function and prevent alveolar capillary leak after oxygen exposure, demonstrating the protective role of SP-B during oxygen-induced lung injury.
Tokieda
K
K
Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
Ikegami
M
M
Wert
S E
SE
Baatz
J E
JE
Zou
Y
Y
Whitsett
J A
JA
D000818:Animals; D002417:Cattle; D006579:Heterozygote; D008171:Lung Diseases / Q000139:chemically induced* / Q000188:drug therapy*; D051379:Mice; D009154:Mutation; D010100:Oxygen / Q000633:toxicity*; D011510:Proteolipids / Q000008:administration & dosage / Q000235:genetics; D011663:Pulmonary Surfactants / Q000008:administration & dosage / Q000235:genetics
D011510:Proteolipids; D011663:Pulmonary Surfactants; D010100:Oxygen