Characteristics of surfactant from SP-A-deficient mice.
Mice that are surfactant protein (SP) A deficient [SP-A(-/-)] have no apparent abnormalities in lung function. To understand the contributions of SP-A to surfactant, the biophysical properties and functional characteristics of surfactant from normal [SP-A(+/+)] and SP-A(-/-) mice were evaluated. SP-A-deficient surfactant had a lower buoyant density, a lower percentage of large-aggregate forms, an increased rate of conversion from large-aggregate to small-aggregate forms with surface area cycling, increased sensitivity to inhibition of minimum surface tension by plasma protein, and no tubular myelin by electron microscopy. Nevertheless, large-aggregate surfactants from SP-A(-/-) and SP-A(+/+) mice had similar adsorption rates and improved the lung volume of surfactant-deficient preterm rabbits similarly. Pulmonary edema and death caused by N-nitroso-N-methylurethane-induced lung injury were not different in SP-A(-/-) and SP-A(+/+) mice. The clearance of 125I-labeled SP-A from lungs of SP-A(-/-) mice was slightly slower than from SP-A(+/+) mice. Although the absence of SP-A changed the structure and in vitro properties of surfactant, the in vivo function of surfactant in SP-A(-/-) mice was not changed under the conditions of these experiments.
Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
M
M
Ikegami
T R
TR
Korfhagen
J A
JA
Whitsett
M D
MD
Bruno
S E
SE
Wert
K
K
Wada
A H
AH
Jobe
D000327:Adsorption; D000818:Animals; D000831:Animals, Newborn; D001798:Blood Proteins / Q000378:metabolism; D003433:Crosses, Genetic; D003643:Death; D005260:Female; D005865:Gestational Age; D008168:Lung / Q000502:physiology* / Q000503:physiopathology; D055370:Lung Injury; D051379:Mice; D018345:Mice, Knockout; D009605:Nitrosomethylurethane; D011247:Pregnancy; D011510:Proteolipids / Q000235:genetics / Q000502:physiology*; D011654:Pulmonary Edema / Q000139:chemically induced / Q000503:physiopathology; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011817:Rabbits; D011995:Recombination, Genetic
D001798:Blood Proteins; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D009605:Nitrosomethylurethane