Changes in erythrocyte glutathione and plasma membrane calcium pump in preterm newborns treated antenatally with MgSO4.

BACKGROUND

Magnesium is required for the proper activity of many metabolic pathways in every cell type. Mg deficiency gives rise to preterm birth and low body weight that are associated with pathological circumstances, including disturbed ions homeostasis and insufficient antioxidant protection. Antenatal MgSO(4) treatment has been reported to exhibit a protective effect on the developing fetus; however, the molecular mechanism of this protection remains not fully understood.

OBJECTIVES

Since Mg ions very rapid cross the placenta, our study tested the hypothesis whether prenatal exposure to MgSO(4) may modify the expression and activity of erythrocyte plasma membrane calcium pump (PMCA), and total erythrocyte glutathione (GSH) concentration in preterm newborns.

METHODS

Immunocharacteristics of erythrocyte PMCA in control and MgSO(4)-treated newborns were done using general and isoform-specific antibodies. The hydrolytic activity of PMCA was determined with and without calmodulin. Total GSH erythrocyte levels were analyzed by a quantitative assay using Ellman reagent. All assays were done after delivery and 24 h later.

RESULTS

Significant differences were present in PMCA amount, isoform composition, basal activity and sensitivity for stimulation by calmodulin in both groups of neonates. The total GSH content altered during examined time, but only in the control group.

CONCLUSIONS

Prenatal treatment with MgSO(4) may exert a significant influence on calcium homeostasis and nonenzymatic antioxidant reserve in the erythrocytes of preterm newborns.