Vitamin D receptor gene ablation in the conceptus has limited effects on placental morphology, function and pregnancy outcome

Vitamin D deficiency has been implicated in the pathogenesis of several pregnancy complications attributed to impaired or abnormal placental function, but there are few clues indicating the mechanistic role of vitamin D in their pathogenesis. To further understand the role of vitamin D receptor (VDR)-mediated activity in placental function, we used heterozygous Vdr ablated C57Bl6 mice to assess fetal growth, morphological parameters and global gene expression in Vdr null placentae. Twelve Vdr+/- dams were mated at 10-12 weeks of age with Vdr+/- males. At day 18.5 of the 19.5 day gestation in our colony, females were euthanised and placental and fetal samples were collected, weighed and subsequently genotyped as either Vdr+/+, Vdr+/- or Vdr-/-. Morphological assessment of placentae using immunohistochemistry was performed and RNA was extracted and subject to microarray analysis. This revealed 25 genes that were significantly differentially expressed between Vdr+/+ and Vdr-/- placentae. The greatest difference was a 6.47-fold change in expression of Cyp24a1 which was significantly lower in the Vdr-/- placentae (P