435. Int J Radiat Oncol Biol Phys. 1984 Mar;10(3):375-8.
Radiation induced secretion of surfactant from cell cultures of type II
pneumocytes: an in vitro model of radiation toxicity.
Shapiro DL, Finkelstein JN, Rubin P, Penney DP, Siemann DW.
The pathogenesis of pneumonitis and fibrosis secondary to lung irradiation is
incompletely understood. The role of the type II alveolar epithelial pneumocyte
in these processes has been under investigation. The type II pneumocyte has been
shown in vivo to respond to radiation induced injury with release of pulmonary
surfactant. The effect of irradiation on cell cultures of type II pneumocytes was
studied to determine if this could be reproduced in vitro. Type II pneumocytes
were found to release surfactant material with a threshold of radiation dose
between 1000 and 1500 rad. This is similar to the dosage range over which the
same effect has been demonstrated in vivo. Experimental results support the
concept that the release of surfactant is not due to either cell disruption or
non-specific release of phospholipid from cell membranes. Irradiation appears to
trigger membrane receptor mediated surfactant release. In addition, irradiation
abolishes the ability of cells to subsequently respond to a physiologic agonist,
suggesting radiation induced damage to the secretory mechanism. These studies
establish that surfactant release in response to irradiation in vivo is a direct
effect on type II pneumocytes. Cell cultures of type II pneumocytes can serve as
a laboratory model of lung cell radiation toxicity.
PMID: 6546743 [PubMed - indexed for MEDLINE]