Neonatal and maternal concentrations of hydroxil radical and total antioxidant system: protective role of placenta against fetal oxidative stress.

BACKGROUND: Reactive oxygen species (ROS) may cause peroxydation of lipids, proteins and deoxyribonucleic acids with subsequent cell damage. The hydroxyl radical (OH*) represents a measure of global oxidative stress. Hydroxyl radicals are short-lived; they form an important part of radical chemistry nonetheless. The measure of total antioxidant system (TAS) can give useful information about the extent of defence capable of counteracting the oxidative damage. Pregnancy is an important condition that favors oxidative stress in the fetus. Clinical studies indicate a protective mechanism against O2 toxicity in the human feto-placental unit.

AIM: This study reports the OH* and TAS concentrations in mother and fetus at birth to evaluate the role of the placenta against fetal oxidative stress.

METHODS: Blood samples were collected at delivery from 45 healthy women at term and from their newborns. The maternal and neonatal OH* and TAS concentrations were compared by paired Student t-test.

RESULTS: OH* was higher in maternal blood than in cord blood (573.75+/- 170.0 UCarr/l vs 40.08+/-33.37 UCarr/l) (p<0.01); TAS concentrations did not differ between the two groups (1.11+/-0.09 mmol/l vs 1.17+/-0.12 mmol/l). Multiple regression analyses: maternal and neonatal OH* decreases with maternal age; only maternal TAS and OH* are related to gestational age in a nonlinear fashion. Female infants showed higher values of maternal and neonatal TAS as compared to male infants.

CONCLUSION: TA protective role of the placenta against oxidative damage is in keeping with a large enough gradient of ROS (between mother and fetus) and the passage of TAS from mother to fetus.