Gene expression in the intestine of newborn piglets after hypoxia-reoxygenation

In preterm infants, intestinal hypoxia may partly contribute to the pathophysiology of necrotizing enterocolitis through changes in gene expression. Splanchnic hypoxia can be detected with monitoring of regional splanchnic oxygen saturation (r_sSO₂). Using a piglet model of asphyxia, we aimed to correlate changes in r_sSO₂ to gene expression.

Forty-two newborn piglets were randomized to control or intervention groups. Intervention groups were subjected to hypoxia until they were acidotic and hypotensive. Next, they were reoxygenated for 30 min according to randomization, i.e., 21% O₂, 100% O₂, or 100% O₂ for 3 min followed by 21% O₂, and observed for 9 h. We continuously measured r_sSO₂ and calculated mean r_sSO₂ and variability of r_sSO₂ (r_sCoVar = SD/mean). Samples of terminal ileum were analyzed for mRNA expression of selected genes related to inflammation, erythropoiesis, fatty acid metabolism, and apoptosis.

The expression of selected genes was not significantly different between control and intervention groups. No associations between mean r_sSO₂ and gene expression were observed. However, lower r_sCoVar was associated with the upregulation of apoptotic genes and the downregulation of inflammatory genes (P < 0.05).

Our study suggests that hypoxia and reoxygenation cause reduced vascular adaptability, which seems to be associated with the upregulation of apoptosis and downregulation of inflammation.

Our results provide important insight into the (patho)physiological significance of changes in the variability of r_sSO₂. Our findings may advance future research and clinical practice regarding resuscitation strategies of preterm infants.