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 72hr. 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 72hr, (2) increased p-eNOS at 48 hr, (3) no differences in total NOx production, (4) increased p-ERK at 24, 48 and 72hr, (5) increased p-AKT at 24hr (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.