Histological evaluation of vitamin-D deficiency on the endometrial decidualization in early pregnancy in rat model

Abstract

ABSTRACTIntroduction: Vitamin-D is a pleiotropic secosteroid hormone that exerts classical effect in calcium uptake and bonemetabolism. In addition, it has non-classical effects on variety of organs. Endometrial decidualization, placentation, and thedevelopment of the embryo itself have all pivotal roles for normal pregnancy outcomes after embryo implantation. Earlymaternal decidua and fetal trophoblast cells illustrate expression of vitamin-D receptor and 1α-hydroxylase enzyme thatcatalyzes vitamin-D into the active metabolite, calcitriol.Aim: To record the histological effect of vitamin-D deficiency on endometrial decidualization during early pregnancy on day8 post-coitum.Materials and Methods: Thirty female albino rats were divided into 2 groups: control group (GpI) and vitamin-D deficientgroup (GpII). After establishment of pregnancy, the animals were sacrificed on the 8th gestational day. The bicornuate pregnantuteri were processed for histological analysis using H&E and PAS stains in addition to immunohistochemical staining forosteopontin (OSP), as a marker for decidualization, and for CD34 to assess the decidual angiogenesis. Morphometric andstatistical 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 remarkablyimpaired stromal cells differentiation. PAS staining illustrated fewer PAS positively stained uterine natural killer cells comparedto control. Weak cytoplasmic OSP immunostaining was observed in the luminal as well as glandular epithelium, vascularendothelium and few stromal cells in mesometrial region. CD34 immunostaining demonstrated impaired angiogenesis in thelateral 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 andweakens decidual angiogenesis during early pregnancy in rat model.