Systemic and cerebral inflammatory response to umbilical cord occlusions with worsening acidosis in the ovine fetus.

OBJECTIVE

We hypothesized that repetitive umbilical cord occlusions (UCOs) with worsening acidosis will lead to a fetal inflammatory response.

STUDY DESIGN

Chronically instrumented fetal sheep underwent a series of UCOs until fetal arterial pH decreased to <7.00. Maternal and fetal blood samples were taken for blood gases/pH and plasma interleukin (IL)-1B and IL-6 levels. Animals were euthanized at 24 hours of recovery with brain tissue processed for subsequent measurement of microglia and mast cell counts.

RESULTS

Repetitive UCOs resulted in a severe degree of fetal acidemia. Fetal plasma IL-1B values were increased approximately 2-fold when measured at maximal fetal acidosis and again at 1-2 hours of recovery. Fetal microglia cells were increased approximately 2-fold in the white matter and hippocampus, while mast cells were increased approximately 2-fold in the choroid plexus and now evident in the thalamus when analyzed at 24 hours recovery.

CONCLUSION

Repetitive UCOs leading to severe acidemia in the ovine fetus near term will result in an inflammatory response both systemically and locally within the brain.