Dysfunction of guinea-pig pulmonary surfactant and type II pneumocytes after repetitive challenge with aerosolized ovalbumin.
BACKGROUND
Asthma symptoms may partially be caused by a surfactant dysfunction. The inflammatory reaction, so characteristic of asthma, involves a protein invasion of airways which harmfully affects the surfactant function. However, mild asthma attacks might also impede the surfactant synthesis in alveolar type II cells.


OBJECTIVE
The present study evaluates the hypothesis that type II pneumocyte metabolic function might be disturbed in a model of mild asthma.


METHODS
Immunized, as well as not immunized control guinea-pigs, were challenged three times at two-day intervals with 0.04% ovalbumin aerosol. Bronchoalveolar lavage (BAL) was performed one day after the last challenge and the fluid was evaluated for surface activity, and content of phospholipids and proteins. Alveolar type II cells were isolated and their ability to incorporate a 3H labeled surfactant precursor was evaluated.


RESULTS
BAL fluid from immunized and challenged animals showed less surface activity (P < 0.01) when compared with BAL fluid from controls, not immunized but challenged. Most likely the reduced surface activity was caused by a 74% increase in the protein concentration (P < 0.05). Isolated type II cells from immunized and challenged animals had 33% less phospholipids than cells from controls (P < 0.05), and phosphatidylcholine synthesis was reduced 35% (P < 0.05).


CONCLUSIONS
These results suggest that the synthesis, intra-cellular storage, and biophysical activity of surfactant are decreased in an intermittent and mild form of asthma.
Liu
M
M
Perinatal Center, Department of Gynecology and Obstetrics, State University of New York at Buffalo, 14222, USA.
Wang
L
L
Holm
B A
BA
Enhorning
G
G
D000485:Allergens; D000818:Animals; D001249:Asthma / Q000139:chemically induced / Q000503:physiopathology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D006168:Guinea Pigs; D008168:Lung / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D010047:Ovalbumin; D011663:Pulmonary Surfactants / Q000096:biosynthesis*
D000485:Allergens; D011663:Pulmonary Surfactants; D010047:Ovalbumin