Properties of lavage material from excised lungs ventilated at different temperatures

Abstract

We studied the phospholipid (PL) and protein contents, the PL composition, and some of the surface properties of lavage materials obtained from freshly excised rat lungs and excised lungs which had been ventilated at different temperatures (22, 37, and 42° C). Ventilation (60 breaths/min) was carried out at constant tidal volume with periodic sighs for one hour. Although there is slightly more lavageable PL and protein in lungs ventilated at 22° C than in freshly excised lungs, there is no difference in the PL composition or surface properties of lavage materials from these lungs. However, as the temperature at which lungs are ventilated is increased to 37° and 42° C, there is(are): 1) a reduction in lavage fluid PL, 2) a reduction in the relative amounts of total phosphatidylcholines (PC) and disaturated PC (DSPC), the major surface active component of pulmonary surfactant, 3) an increase in unsaturated PC, and 4) increases in total protein and nonsedimentable protein (100,000 g; 2 hr) in the lavage materials. There are also differences in the surface properties of the lavage materials from lungs ventilated at higher temperatures when compared with freshly excised lungs or lungs ventilated at 22° C, probably as a result of the changes in composition. Maximal surface tension is greater for lavage materials from lungs ventilated at 37° C. For lungs ventilated at 42° C, maximal and minimal surface tension values are increased. These results demonstrate that there are differences in the composition and surface properties of alveolar lavage materials from excised lungs ventilated at different temperatures.