Background & Aim: The receptor for Advanced Glycation End products (RAGE) is implicated in the pathogenesis of diabetic complications, but its importance for the induction of congenital malformations in diabetic pregnancy is unclear. The aim of the present study was to investigate a possible role of RAGE activation in the induction of diabetic embryopathy.
Methods: Female non-diabetic and diabetic wildtype (WT) C57Bl/6 mice and RAGE knockout C57Bl/6 (RAGE‑/-) mice were mated with males of the same genotype. Diabetes was induced by daily streptozotocin (STZ) injections (50 mg/kg STZ i.p.) on five consecutive days. On gestational day 18, pregnant mice were anesthetized and blood was drawn from the heart to measure maternal metabolic parameters. Fetuses and placentas were excised, weighed, and examined for morphological anomalies, and fetal livers were analyzed for 8‑iso‑PGF2α levels.
Results: There were no malformations in non-diabetic WT or non-diabetic RAGE‑/- mice. However, resorption rates were higher in non-diabetic WT (10%) than in non-diabetic RAGE‑/- mice (4%). Diabetic WT mice had higher malformation (22%) and resorption (43%) rates than diabetic RAGE‑/- mice (3% malformations and 21% resorptions). Maternal diabetes decreased fetal weight more in WT fetuses (44%) than in RAGE‑/- fetuses (36%). There were no differences in plasma glucose levels between the diabetic WT and RAGE‑/- mice, but plasma levels of triglycerides and cholesterol were lower in diabetic WT mice than in diabetic RAGE-/- mice. Diabetes increased maternal plasma levels of methylglyoxal in WT and RAGE‑/- mice, and increased fetal hepatic levels of 8-iso-PGF2α in WT fetuses, but not in RAGE‑/- fetuses.
Discussion: Knockout of RAGE diminished the rates of fetal malformations and resorptions, despite similar levels of hyperglycemia in pregnant diabetic mice. An anti-teratogenic effect was present in RAGE‑/- mice despite having a more severe diabetic state than diabetic WT mice. As 8-iso-PGF2α, a marker of oxidative stress, only increased in diabetic WT offspring, this suggested a pivotal role of RAGE activation and oxidative stress in the pathogenesis of diabetic embryopathy.
2016. Vol. 62, 62-70 p.
Diabetes; AGE; RAGE; Oxidative stress; Diabetic embryopathy; Neural tube defects; Experimental teratology