Respiratory distress after intratracheal bleomycin: selective deficiency of surfactant proteins B and C.

Savani RC, Godinez RI, Godinez MH, Wentz E, Zaman A, Cui Z, Pooler PM, Guttentag SH, Beers MF, Gonzales LW, Ballard PL
Am J Physiol Lung Cell Mol Physiol. 2001 281 (3): L685-96

PMID: 11504697 · DOI:10.1152/ajplung.2001.281.3.L685

Intratracheal bleomycin in rats is associated with respiratory distress of uncertain etiology. We investigated the expression of surfactant components in this model of lung injury. Maximum respiratory distress, determined by respiratory rate, occurred at 7 days, and surfactant dysfunction was confirmed by increased surface tension of the large-aggregate fraction of bronchoalveolar lavage (BAL). In injured animals, phospholipid content and composition were similar to those of controls, mature surfactant protein (SP) B was decreased 90%, and SP-A and SP-D contents were increased. In lung tissue, SP-B and SP-C mRNAs were decreased by 2 days and maximally at 4--7 days and recovered between 14 and 21 days after injury. Immunostaining of SP-B and proSP-C was decreased in type II epithelial cells but strong in macrophages. By electron microscopy, injured lungs had type II cells lacking lamellar bodies and macrophages with phagocytosed lamellar bodies. Surface activity of BAL phospholipids of injured animals was restored by addition of exogenous SP-B. We conclude that respiratory distress after bleomycin in rats results from surfactant dysfunction in part secondary to selective downregulation of SP-B and SP-C.

MeSH Terms (16)

Animals Bleomycin Bronchoalveolar Lavage Fluid Fluorescent Antibody Technique, Indirect Injections Lung Male Microscopy, Electron Phospholipids Proteolipids Pulmonary Surfactants Rats Rats, Sprague-Dawley Respiratory Insufficiency Tissue Distribution Trachea

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