Teratogenic Predisposition in Diabetic Rat Pregnancy

Sammanfattning: Pre-gestational diabetes increases the risk of congenital malformation in the offspring and both morbidity and mortality in the diabetic mother and her offspring. During pregnancy, high glucose levels act as a teratogen through several cellular and biochemical pathways and increased production of reactive oxygen species (ROS) has a central role in diabetic embryopathy. The aim of this work was to investigate the importance of genetic predisposition for congenital malformations and to study the genes involved in the teratogenic process of diabetic pregnancy.The crossbreeding of two rat strains, with both low and high incidence of diabetes-induced malformations, indicated that strain-specific maternal factors, such as disturbed serum levels of amino acids, triglycerides, and ?-hydroxybutyrate, were associated with malformation. In addition, disturbed fetal expression of genes involved in ROS defense and development (Shh, Bmp4, Ret and Gdnf) in mandible and heart, and decreased activity of Gapdh and Aldose Reductase were associated with the teratogenic process, and the trans-generational heredity of the mother determined the type of malformations induced by maternal diabetes.In rat embryos, a diabetic environment in utero changed the expression of genes involved in ROS defense (Nrf2, Gpx1 and Cat), development of mandible and heart (Msx2, Shh, Bmp4, Ret and Gdnf), and neural tube closure and apoptosis (Pax3 and p53). The changes were divergent with tissue-specific alterations of gene expression in developing mandible, heart anlage, and whole embryo.Disruption of the Receptor for Advanced Glycation End products (RAGE) had a protective effect against diabetic embryopathy in mice, and the blockage of RAGE diminished ROS production in the offspring: this supported oxidative stress being a necessary etiological component in diabetic embryopathy.Maternal metabolic state and genetic susceptibility influence fetal outcome in experimental diabetic pregnancy. Disturbed protection against oxidative stress and tissue-specific derangements in the expression of developmental genes play pivotal roles in the teratogenic mechanism, and enhanced levels of Advanced Glycation End products (AGE) and RAGE-induced oxidative stress are involved in diabetic dysmorphogenesis.