Cauterization of Meso-ovarian Vessels, a New Model of Intrauterine Growth Restriction in Rats

Intrauterine growth restriction (IUGR) remains an important cause of perinatal morbidity and mortality. Both IUGR and low birth weight have been identified as risk factors for increased incidence of cardiovascular disease, dyslipemia, and other diseases in the adulthood.Several animal models have been developed to study the underlying mechanisms of IUGR and its later consequences, with utero-placental ischemia by uterine artery ligation (UAL) being the most frequently used in rats. The relevance of this model lies in the fact that it induces altered placental perfusion, the main cause of IUGR in humans in Western countries. However, there is also controversy over the grade and homogeneity of IUGR obtained.In this study, we propose a new animal model of IUGR related to placental ischemia through the cauterization of meso-ovarian vessels. We aimed to test the feasibility of meso-ovarian vessel cauterization (CMO), and to compare it with uterine artery ligation (UAL). The CMO group had similar incidence of perinatal mortality, percentage of IUGR, and evolution of body weight during early extrauterine life to the UAL group, indicating that both methods are similarly efficient for inducing IUGR. Moreover, both of them affect the ratio of fetal to placental weight, and the weight of vital organs, supporting the hypothesis of a fetal compensatory response or “brain- and heart-sparing effect”. Both operative models suffer approximately 50% perinatal mortality, implying that they are both more efficient in the production of IUGR when C-section is performed. On the other hand, CMO was significantly faster to perform than UAL and seemed to produce a more uniform ischemia throughout the uterus than the UAL method, resulting in a more homogeneous group of IUGR pups.