Ligation of the Uterine Artery and Early Postnatal Food Restriction – Animal Models for Growth Retardation

Intrauterine growth restriction (IUGR) is one of the major causes of short stature in child- and adulthood. The cause of IUGR is unknown, however, an impaired uteroplacental function during the second half of human pregnancy might be an important factor, by affecting the programming of somatotropic axis and leading to postnatal growth failure into adulthood. Two rat models with perinatally induced growth retardation were used to examine the long-term effects of perinatal insults on growth. IUGR rats were prepared from pregnant dams, with a bilateral uterine artery ligation at day 17 of their pregnancy. Since the rat is relatively immature at birth, an early postnatal food restriction model was included as another model to broaden the time window of sensitive period of organogenesis. An individual growth curve was calculated of each animal (n = 813). From these individual growth curves the predicted growth curve for each experimental group was calculated by multilevel analysis. The proposed mathematical model allows us to estimate the growth potentials of these rat models with precision and could provide basic information to investigate the relationships among a number of other variables in future studies. Furthermore, we concluded that both pre- and early postnatal malnutrition leads to irreversible slowing down of postnatal growth.