AJP - Lung Cellular and Molecular Physiology, Vol 268, Issue 2 181-L186, Copyright © 1995 by American Physiological Society
A type I cell-specific protein is a biochemical marker of epithelial injury in a rat model of pneumonia
M. C. McElroy, J. F. Pittet, S. Hashimoto, L. Allen, J. P. Wiener-Kronish and L. G. Dobbs
Department of Anesthesia, University of California, San Francisco 94143.
In this study we determined whether the alveolar fluid content of a
specific epithelial type I cell protein, rTI40, can be used as a
biochemical marker for lung injury. A model of alveolar epithelial injury
was developed by instilling Pseudomonas aeruginosa bacteria (PA103) into
the airspaces of anesthetized, ventilated rats. After 6 h, the alveolar
fluid content of rTI40 from PA103-treated rats was increased over 80-fold
in comparison to alveolar fluid from control rats (P < 0.05). This
increase in rTI40 correlated with both morphological evidence of injury to
alveolar epithelial type I cells and increased permeability of the alveolar
epithelium to protein tracers. In contrast, the lactate dehydrogenase
activity of alveolar fluid from PA103-treated rats was elevated only
threefold over control values at 6 h (P < 0.05). In a second study using
a less injurious strain of P. aeruginosa (PA103 exsA::omega), the alveolar
fluid content of rTI40 was the same as control values. These findings
indicate that the alveolar fluid content of a type I cell-specific protein
can be used as a sensitive and specific biochemical marker of type I cell
injury.
