Journal of Applied Physiology, Vol 51, Issue 3 646-653, Copyright © 1981 by American Physiological Society
Surfactant aggregation in rat lungs: influence of temperature and ventilation
D. Massaro, L. Clerch and G. D. Massaro
We examined the effect of the ventilatory rate and the temperature of
excised lungs and of increased body temperature of anesthetized
spontaneously breathing rats on the centrifugal sedimentation of
disaturated phosphatidylcholine (DSPC) present in lung lavage returns. More
DSPC sedimented from lungs ventilated at low than at high rates, and
sedimentation of DSPC and lung volume loss were temperature dependent, 41
greater than 37 greater than 4 degrees C. Most of the noncellular
sedimented material was tubular and common myelin; these had diminished
ability to lower surface tension rapidly compared with less-aggregated
surfactant. More aggregated DSPC accumulated and lung volume decreased more
in spontaneously breathing rats anesthetized for 30 min than in rats killed
immediately after being anesthetized; these changes were greater after 30
min of anesthesia in hyperthermic rats (40.4 +/- 0.3 degrees C) than in
normothermic rats (37.4 +/- 0.1 degrees C). These studies have shown a
correlation between the increased accumulation of surfactant as large
aggregates and the loss of alveolar stability; however, a cause and effect
between these events has not yet been shown.
