Acute pathophysiological responses in the normal lungs of newborn piglets exposed to pure oxygen

We investigated the effect of short-term pure oxygen treatment on pulmonary function, serum cytokine levels, and apoptosis in the lungs of healthy newborn piglets.

Twelve newborn piglets were randomly assigned to receive pure oxygen (OXY) (N.=6) or room air (AIR: 21% oxygen) (N.=6) for 4 hours. Cardiopulmonary function serum levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF) α were evaluated. Histology was used to assess apoptosis and morphological differences between treatment groups.

Four-hour treatment with 100% oxygen resulted in higher PaO2, AaDO2, and compliance of the respiratory system (Crs) in the OXY than in the AIR animals. Serum levels of IL-6 were significantly higher in OXY piglets compared with AIR piglets (P=0.009), but there were no differences between groups in the serum levels of IL-1ß and TNF-α (P=0.640 and P=0.306, respectively). The piglets in the OXY group had a greater average number of apoptotic cells in the lung than AIR piglets, although this did not reach statistical significance.

Our findings indicate that treatment with 100% oxygen for 4 hours may have clinical benefit by improving pulmonary function in normal neonates with limited increases in the inflammation and apoptosis.