Tolerance of SP-A-deficient mice to hyperoxia or exercise.
Mice carrying a null mutation of the surfactant-associated protein A (SP-A) gene have normal respiratory function, but their surfactant lacks tubular myelin, is sensitive to protein inactivation in vitro, and contains decreased pool sizes of the biophysically active large-aggregate surfactant. We hypothesized that SP-A-deficient mice would be more susceptible to exercise-induced stress and O(2)-induced lung injury. SP-A-(-/-) and SP-A-(+/+) mice tolerated 1 h of swimming or 45 min of running on a treadmill at 15 m/min equivalently, without alterations of the amount of alveolar saturated phosphatidylcholine. After 3 days of hyperoxia, SP-A-(-/-) mice had increased alveolar protein, but pressure-volume curves were not different between groups. Alveolar protein concentration was similarly increased in SP-A-(-/-) and SP-A-(+/+) mice after 4 days of exposure to hyperoxia. Survival rates were similar after 4 days of hyperoxia. SP-A-(-/-) mice were equally tolerant to exercise and 4 days of hyperoxia, indicating that the SP-A-dependent alterations in surfactant did not result in functional deficits.
Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA. machiko.ikegami@chmcc.org
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Ikegami
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Jobe
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Whitsett
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Korfhagen
D000818:Animals; D018496:Hyperoxia / Q000097:blood / Q000503:physiopathology*; D051379:Mice; D008815:Mice, Inbred Strains; D010713:Phosphatidylcholines / Q000097:blood; D005082:Physical Exertion / Q000502:physiology*; D011510:Proteolipids / Q000097:blood / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000097:blood / Q000378:metabolism*; D012129:Respiratory Function Tests; D012420:Running / Q000502:physiology; D013550:Swimming / Q000502:physiology
D010713:Phosphatidylcholines; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants