OC02.02: Selective ligature of the uteroplacental vessels in pregnant rabbit is more suitable model of intrauterine growth restriction than hyponutrition

Abstract

Objective: To compare an animal model of growth restriction by selective ligature of uteroplacental vessels with a model of severe hyponutrition. Methods: 16 New Zealand pregnant rabbits were included in the placental insufficiency (PI) model, in which a 40–50% of uteroplacental vessels were ligated at 25d of gestation. Contralateral horn were considered as control. After surgery, dams were allowed free access to water and standard chow. 2 New Zealand pregnant rabbits were included in the hyponutrition (HN) model, in which a sham-surgery was performed at 25d. After surgery, hyponutrition was induced by restricting up to 70% of the normal diet. Pulsed Doppler assessment was performed before Cesarean delivery. Results: Mortality rate showed significant differences between experimental groups (14,3% control; 5.0% HN; and 54.2% PI (p<0.001)). Among survivors, all biometric parameters showed a consistent and significant gradient across the experimental groups. Doppler assessment demonstrated a significant linear increase of ductus venosus and a linear decrease of umbilical vein blood flow across study groups. Additionally, umbilical artery and aortic isthmus showed a non-significant trend to increase through experimental groups. Conclusion: Selective ligature of uteroplacental vessels results in an animal model of fetal growth restriction with biometric and hemodynamic changes that closely resembles the clinical condition. This surgical model could be useful to investigate effects of hypoxic condition on different key organs, such as brain and heart.