L G Thaete1, M G Neerhof, M S Caplan. 1. Department of Obstetrics and Gynecology, Northwestern University Medical School, Evanston Hospital, IL 60201, USA.
Abstract
OBJECTIVE: Our purpose was to investigate the hypothesis that endothelin plays a critical role in maternal hypoxia-induced intrauterine growth restriction. STUDY DESIGN: Chronic indwelling venous and arterial catheters were placed on day 17 of a 22-day gestation in timed-pregnant Sprague-Dawley rats. Twelve rats were infused with saline solution and 12 with 6 mg/kg per day FR139317, an endothelin receptor A-specific antagonist. For gestational days 18 to 21 half the rats in each infusion group were housed in a normoxic environment and the other half in a hypoxic (14% oxygen) environment. On day 21 an arterial blood gas level was determined, the rats were then anesthetized, and a hysterotomy was performed. The weight of each pup and its corresponding placenta was recorded. Statistical significance was determined by analysis of variance. RESULTS: Among the rats receiving saline solution infusions, fetal weights were 20% less and placental weights were 11% less for those housed in a hypoxic environment compared with those housed in a normoxic environment (p < 0.003). Among the rats receiving FR139317 infusions, fetal and placental weights were not significantly different for those in a hypoxic environment compared with those in a normoxic environment. The fetal and placental weights for the rats receiving FR139317 infusion in hypoxic or normoxic environments were similar to those receiving saline solution in a normoxic environment. CONCLUSIONS: Endothelin plays a critical role in hypoxia-induced intrauterine growth restriction. Infusion of an endothelin antagonist prevents the intrauterine growth restriction caused by chronic hypoxia.
OBJECTIVE: Our purpose was to investigate the hypothesis that endothelin plays a critical role in maternal hypoxia-induced intrauterine growth restriction. STUDY DESIGN: Chronic indwelling venous and arterial catheters were placed on day 17 of a 22-day gestation in timed-pregnant Sprague-Dawley rats. Twelve rats were infused with saline solution and 12 with 6 mg/kg per day FR139317, an endothelin receptor A-specific antagonist. For gestational days 18 to 21 half the rats in each infusion group were housed in a normoxic environment and the other half in a hypoxic (14% oxygen) environment. On day 21 an arterial blood gas level was determined, the rats were then anesthetized, and a hysterotomy was performed. The weight of each pup and its corresponding placenta was recorded. Statistical significance was determined by analysis of variance. RESULTS: Among the rats receiving saline solution infusions, fetal weights were 20% less and placental weights were 11% less for those housed in a hypoxic environment compared with those housed in a normoxic environment (p < 0.003). Among the rats receiving FR139317 infusions, fetal and placental weights were not significantly different for those in a hypoxic environment compared with those in a normoxic environment. The fetal and placental weights for the rats receiving FR139317 infusion in hypoxic or normoxic environments were similar to those receiving saline solution in a normoxic environment. CONCLUSIONS: Endothelin plays a critical role in hypoxia-induced intrauterine growth restriction. Infusion of an endothelin antagonist prevents the intrauterine growth restriction caused by chronic hypoxia.