title: Increased phospholipase A2 and lyso-phosphatidylcholine levels are associated with surfactant dysfunction in lung contusion injury in mice.
abstract: OBJECTIVE
  Surfactant dysfunction is an important pathologic disturbance in various forms of acute inflammatory lung injury. Previously we reported the presence of marked alterations in the composition and activity of pulmonary surfactant in bilateral lung contusions (LC) injury induced by blunt trauma in rats. This is extended here to a mouse model of unilateral LC with a focus on compositional and functional changes in surfactant associated with permeability injury and increases in activity of secretory phospholipase A2.
  
  
  RESULTS
  Surfactant-associated gene expression was not altered in mice with unilateral LC injury on the basis of Affymetrix analysis. LC mice had significant permeability injury with increased albumin and total protein in bronchoalveolar lavage at 5, 24, 48, and 72 hours after insult compared with uninjured controls. The percent content of large surfactant aggregates was depleted at all postinjury times, and pulmonary pressure-volume (P-V) mechanics and compliance were abnormal during this period. Surfactant dysfunction was evaluated in 24 hours, when permeability injury and P-V changes were most prominent. At this time, activity levels of secretory phospholipase A2 were increased in bronchoalveolar lavage, and chromatographic analysis showed that large surfactant aggregates had decreased levels of phosphatidylcholine and increased levels of lyso-phosphatidylcholine. These changes were accompanied by severe detriments in large aggregate surface activity by pulsating bubble surfactometry. Large aggregates from LC mice at 24 hours had minimum surface tensions of only 12.6 ± 1.1 mN/m after prolonged bubble pulsation (20 min) compared with 0.7 ± 0.03 mN/m for uninjured controls.
  
  
  CONCLUSIONS
  These results document important detriments in the composition and activity of pulmonary surfactant in LC injury in mice and suggest that active synthetic phospholipase-resistant exogenous surfactants may have utility in treating surfactant dysfunction in this clinically important condition.
authors.affiliation: Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: David
authors.initials: D
authors.lastname: Machado-Aranda
authors.forename: Zhengdong
authors.initials: Z
authors.lastname: Wang
authors.forename: Bi
authors.initials: B
authors.lastname: Yu
authors.forename: M V
authors.initials: MV
authors.lastname: Suresh
authors.forename: Robert H
authors.initials: RH
authors.lastname: Notter
authors.forename: Krishnan
authors.initials: K
authors.lastname: Raghavendran
mesh_terms: D055371:Acute Lung Injury / Q000378:metabolism* / Q000503:physiopathology; D000418:Albumins / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D003288:Contusions / Q000378:metabolism* / Q000503:physiopathology; D004797:Enzyme-Linked Immunosorbent Assay; D008244:Lysophosphatidylcholines / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D020411:Oligonucleotide Array Sequence Analysis; D010713:Phosphatidylcholines / Q000378:metabolism; D054497:Phospholipases A2, Secretory / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D037661:Pulmonary Surfactant-Associated Proteins / Q000378:metabolism; D012129:Respiratory Function Tests
chemical_list: D000418:Albumins; D015415:Biomarkers; D008244:Lysophosphatidylcholines; D010713:Phosphatidylcholines; D010743:Phospholipids; D037661:Pulmonary Surfactant-Associated Proteins; D054497:Phospholipases A2, Secretory