ABSTRACT
Introduction: Vitamin-D is a pleiotropic secosteroid hormone that exerts classical effect in calcium uptake and bone
metabolism. In addition, it has non-classical effects on variety of organs. Endometrial decidualization, placentation, and the
development of the embryo itself have all pivotal roles for normal pregnancy outcomes after embryo implantation. Early
maternal decidua and fetal trophoblast cells illustrate expression of vitamin-D receptor and 1α-hydroxylase enzyme that
catalyzes vitamin-D into the active metabolite, calcitriol.
Aim: To record the histological effect of vitamin-D deficiency on endometrial decidualization during early pregnancy on day
8 post-coitum.
Materials and Methods: Thirty female albino rats were divided into 2 groups: control group (GpI) and vitamin-D deficient
group (GpII). After establishment of pregnancy, the animals were sacrificed on the 8th gestational day. The bicornuate pregnant
uteri were processed for histological analysis using H&E and PAS stains in addition to immunohistochemical staining for
osteopontin (OSP), as a marker for decidualization, and for CD34 to assess the decidual angiogenesis. Morphometric and
statistical studies were performed.
Results: Substantial decrease in the number of implantation sites in vitamin-D deficient rats was noted by gross examination.
Histological examination revealed significant decrease in endometrial thickness at the antimesometrial region with remarkably
impaired stromal cells differentiation. PAS staining illustrated fewer PAS positively stained uterine natural killer cells compared
to control. Weak cytoplasmic OSP immunostaining was observed in the luminal as well as glandular epithelium, vascular
endothelium and few stromal cells in mesometrial region. CD34 immunostaining demonstrated impaired angiogenesis in the
lateral decidua as compared to control. These findings were confirmed by morphometric and statistical analysis.
Conclusion: Vitamin-D deficiency impairs the uterine stromal cells differentiation, affects the immunity tolerance and
weakens decidual angiogenesis during early pregnancy in rat model.