Increased surface tension of the lung and surfactant in bleomycin-induced pulmonary fibrosis in rats.
The increased elastic recoil of the lung in bleomycin-induced pulmonary fibrosis in the rat is due in part to increased surface forces. This study was designed to determine the role of surface tension in situ and in vitro 21 d after instillation of bleomycin. Using sequentially measured pressure-volume curves generated with air, saline, air after lavage with Tween 20, and saline, surface tension was significantly higher in bleomycin-treated lungs than in untreated lungs (4.7 +/- 1.1 versus 1.8 +/- 0.2 dyne/cm, p < 0.01). Surface tension was determined in vitro with a Wilhelmy balance using bronchoalveolar lavage fluid, surfactant, and organic solvent lipid extracts of surfactant. Bleomycin treatment resulted in elevated minimal surface tensions: BALF (20.7 +/- 0.6 versus 13.6 +/- 3.8 dyne/cm, p < 0.02), isolated surfactant (12.0 +/- 1.3 versus 3.0 +/- 0.5 dyne/cm, p < 0.02), and the organic solvent lipid extracted surfactant (11.0 versus 3.2 dyne/cm). These results indicate that the physical properties of surfactant in lungs of rats treated with bleomycin are abnormal and contribute to the increased elastic recoil in this model of pulmonary fibrosis.
Department of Pulmonology, Kanto Chuo Hospital, Tokyo, Japan.
T
T
Horiuchi
M
M
Ikegami
R M
RM
Cherniack
R J
RJ
Mason
D000818:Animals; D001761:Bleomycin; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D008168:Lung / Q000187:drug effects / Q000503:physiopathology*; D008170:Lung Compliance / Q000187:drug effects; D011658:Pulmonary Fibrosis / Q000139:chemically induced* / Q000503:physiopathology; D011663:Pulmonary Surfactants / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013500:Surface Tension; D013997:Time Factors
D011663:Pulmonary Surfactants; D001761:Bleomycin