THE EFFECTS OF MECHANICAL STRETCHING ON FETAL-RAT LUNG-CELL PROSTACYCLIN PRODUCTION

A model system was used to determine the effect of stretch on prostacyclin (PGI) production by organotypic fetal rat lung cultures grown on gelatin foam in vitro, measured by RIA of 6-keto-PGF1-alpha (6KF) in the culture medium. The stretching apparatus was programmable for stretch of varying frequency and duration. The effective stimuli for PGI production were: continuous pulsatile stretch > intermittent pulsatile stretch> permanent stretch (p < 0.05). The rate of PGI production was greatest in the first 15 min of pulsatile stretch and was associated with a 70% increase in cAMP production (p < 0.05). When the effect of magnitude of stretch was compared (15% vs 28% extension), there was a significant increase with a maximum in the 28% stretch group double that of the 15% stretch group (p < 0.01). PGI production in response to pulsatile stretching was inhibited by indomethacin but not by pretreatment with cortisol. These results suggest that the production of PGI by lung cells may be significantly affected by the frequency and magnitude of pulsatile stretching.