Indexed on: 22 Dec '09Published on: 22 Dec '09Published in: Metabolism
Gestational diabetes mellitus (GDM) is a commonly encountered disorder of mid to late pregnancy that is characterized by hyperglycemia, hyperinsulinemia, and impaired glucose tolerance. Gestational diabetes mellitus is thought to be multifactorial in origin and derives from both genetic and environmental factors. However, the mechanisms underlying GDM are incompletely understood; and current GDM animal models do not appear to closely mimic the clinical situation in humans. The present study used environmental exposure to high-saturated-fat diet (HFD) in an effort to develop a GDM mouse model that closely simulates metabolic abnormalities seen in human GDM. This model was then used to determine the contributions of HFD-induced placental oxidative stress (OS) and vascular dysregulation, which are observed in GDM patients and are believed to contribute to the pathogenesis of the disease. Pathologic manifestations of the disease were quantified by evaluating the extent of placental lipid peroxidation and by determining protective effects of dietary antioxidant quercetin supplementation to reduce HFD-associated placental OS. In this study, female C57BL/6 mice were fed HFD for 1 month before conception and throughout gestation to mimic chronic maternal fast food consumption. Maternal body weight increased from gestation day (GD) 0 to GD19 by 41% with HFD, as compared with 23% in control dams; HFD dams also developed insulin resistance (66% increase in plasma insulin and 27% increase in plasma glucose levels by GD10) as compared with control dams. Placentas from HFD GD19 dams demonstrated loss of trophoblasts and OS-mediated labyrinthine endothelial cellular damage, the latter of which was prevented with quercetin supplementation. Our findings suggest that prenatal HFD alters glucose metabolism and elevates placental OS, which are believed to collectively relate to improper formation of the conceptus and impaired birth outcome.