Stretch-induced apoptosis in fetal lung cells.

摘要

At birth immature lungs of preterm infants are subjected to continuous mechanical ventilation. Though the effect of physical forces on adult lung is well studied, the effect on the preterm newborn lung is not clearly understood. Apoptosis has been suggested to play a role during mechanical ventilation. Herein, we investigated whether continuous stretch of preterm lungs is associated with an increase in apoptosis. We used the Flexercell Strain unit to stretch day 19 fetal rat lung cells. DNA fragmentation occurred when epithelial, but not fibroblast cells were subjected to continuous cyclic high (20%) stretch. Intermittent stretch and continuous cyclic stretch of lower magnitudes (5 and 10%) did not initiate apoptosis. Furthermore, continuous cyclic high stretch increased activities of caspase 8, 9 and 3 as well as a decrease in mitochondria) membrane potential, implicating both the intrinsic and extrinsic caspase pathways during stretch-induced apoptosis.