Apoptosis and proliferation in lungs of ventilated and oxygen-treated preterm infants

Area of Science:

• Neonatal Physiology
• Respiratory Medicine
• Cell Biology

Background:

• Preterm infants with respiratory distress syndrome often require mechanical ventilation and oxygen therapy.
• These interventions can impact lung development and cellular processes.
• Understanding the cellular responses to ventilation is crucial for improving neonatal lung care.

Purpose of the Study:

• To investigate apoptosis and proliferation in the lungs of mechanically ventilated preterm infants.
• To determine the effect of exogenous surfactant on these cellular processes.
• To explore the role of caspases in ventilation-induced cell death.

Main Methods:

• Analysis of lung tissue from ventilated preterm infants and stillborn fetuses.
• Assessment of apoptotic and proliferating cells using TUNL and Ki-67 labeling.
• Immunolabeling for cleaved caspases-3, -8, and -9 to study cell death pathways.
• Comparison of surfactant-treated and untreated ventilated infants.

Main Results:

• Significantly increased apoptosis and proliferation in ventilated infants' lungs compared to stillborn fetuses.
• Apoptosis observed in alveolar epithelial cells; proliferation in epithelial, endothelial, and smooth muscle cells.
• Surfactant treatment showed a non-significant reduction in apoptosis.
• Caspase-3 involved in ventilation-induced apoptosis, but caspases-8 and -9 were not.

Conclusions:

• Mechanical ventilation and oxygen treatment induce lung epithelial cell apoptosis and proliferation in preterm infants.
• Ventilation affects multiple cell types within the developing lung.
• Caspase-3 plays a role in the observed cell death pathways.