The effects of a cyclo-oxygenase II inhibitor on placental artery production of thromboxane and prostacyclin

Objective The study was undertaken to determine the effects of a cyclo-oxygenase II inhibitor on fetoplacental artery production of prostacyclin and thromboxane A2. Study design Eight placentas were obtained from normal parturients at delivery and four chorionic plate arteries were dissected from each placenta. Arteries were incubated in media alone, media plus angiotensin II (1×10−10 mol), media plus rofecoxib (300 ng/mL), or media plus angiotensin II and rofecoxib. Serial samples were assayed for metabolites of thromboxane B2 and prostacyclin by enzyme-linked immunosorbent assay. Results were compared by analysis of variance, and P<.05 was considered significant. Results At 24 hours, 6-keto-prostaglandin F1α levels in the rofecoxib group (1.74±1.39 ng/mg tissue, P<.01) and the rofecoxib plus angiotensin II group (2.15±1.85 ng/mg tissue, P<.01) were significantly lower than levels in the control group (4.25±2.03 ng/mg tissue). Thromboxane B2 levels were lower in the angiotensin II group (0.65±0.33 ng/mg tissue) than the control group (1.22±0.70 ng/mg tissue, P<.05). Conclusion Cyclo-oxygenase II inhibition decreases the production of prostacyclin in fetoplacental arteries and alters the normal ratio of thromboxane A2 to prostacyclin.