Effect of hypoxia on endothelial nitric oxide synthase, NO production, intracellular survival signaling (p-ERK1/2 and p-AKT) and apoptosis in human term trophoblast.

PROBLEM: Hypoxia is commonly associated with complicated pregnancies such as intrauterine growth restriction. We evaluated the effects of hypoxia on phospho (p)-eNOS, p-ERK, p-AKT and apoptosis in human trophoblast. METHOD OF STUDY: Isolated trophoblast were cultured in 21% oxygen or 2% oxygen for 24, 48 and 72 hr. p-eNOS, p-ERK and p-AKT protein were assessed by Western blot and apoptosis by TUNEL assay. NOx was determined in the culture media.
RESULTS: Compared to controls, hypoxia-exposed CT showed the following: (1) decreased eNOS at 48 and 72 hr, (2) increased p-eNOS at 48 hr, (3) no differences in total NOx production, (4) increased p-ERK at 24, 48 and 72 hr, (5) increased p-AKT at 24 hr (P < 0.05) and (6) increased apoptosis at 48 hr.
CONCLUSION: Hypoxia increases activation of p-ERK and induces apoptosis of cultured trophoblast. Hypoxia decreases overall total eNOS but increases p-eNOS, which may allow for NO production to be maintained in trophoblast cells.