Progesterone partially recovers placental glucose transporters in dexamethasone-induced intrauterine growth restriction

Abstract

Research question: How does progesterone improve fetal outcome and change the expression of placental glucose transporters (GLUT) in dexamethasone-induced intrauterine growth restriction (IUGR)?

Design: A total of 64 rats were divided randomly into four different treatment groups based on daily i.p. injections of either saline or dexamethasone in the presence or absence of progesterone. Injections started on the 15th day of gestation (15dg) and lasted until the day of sacrifice at 19dg or 21dg. Maternal plasma progesterone concentrations were measured by enzyme-linked immunosorbent assay. The gene and protein expression of placental GLUT1 and GLUT3 were evaluated in the placental labyrinth and basal zones by real-time polymerase chain reaction and Western blotting, respectively. The localization of GLUT1 and GLUT3 was evaluated by immunohistochemistry.

Results: Dexamethasone induced significant decreases in maternal serum progesterone concentrations (P = 0.029) and placental (P < 0.001) and fetal body (P = 0.009) weights. Dexamethasone also reduced the expression of GLUT1 in the labyrinth zone (P = 0.028) and GLUT3 in both the labyrinth (P = 0.002) and basal zones (P = 0.026). Coadministration of dexamethasone and progesterone prevented the reduction in fetal body weight, placental weight and placental GLUT expression compared with that seen in dexamethasone-treated groups.

Conclusion: These results suggest that progesterone prevents the significant reduction in fetal and placental weights in dexamethasone-induced IUGR, possibly through improving the expression of placental GLUT.

Keywords: Basal zone; Fetal development; Fetal growth restriction; Labyrinth zone; Placental efficiency; Placental transporters.