ABSTRACT: Fetal growth restriction (FGR) is a severe pregnancy complication often caused by placental insufficiency. Proper trophoblast invasion is essential for placental development and function, ensuring adequate nutrient and oxygen supply to the developing fetus. Dysregulation impairs placental perfusion, leading to FGR. This study uses a calorie-restricted mouse model to investigate genes/molecular mechanisms regulating trophoblast invasion across gestational timepoints. Pregnant mice received either a standard or 50% calorie-restricted diet from E8.5. Placentas and invasion sites were analyzed at E10.5, E12.5, E14.5, E16.5, and E17.5. mRNA sequencing and RT/qPCR examined trophoblast invasion-related genes (Mmp2, Mmp9, Efna1, Rac1, Rras, Ascl2, Tfap2c, Prl7b1) and angiogenesis genes (Vegfa, Vegfb, Pdgf, Akt3). Immunohistochemistry of trophoblast cells (cytokeratin 8, CK8) and endothelial cell markers (endomucin, CD31, CCD105, VEGFR2) was performed. Statistical analysis used Student’s t-test. Caloric restriction significantly reduced fetal/placental weights from E12.5, with persistent growth restriction at E16.5, and E17.5. IHC at E17.5 showed reduced decidual depth, trophoblast invasion distance, and trophoblast quantity within the decidua. This impaired growth was accompanied by reduced expression of trophoblast invasion genes (Mmp2, Mmp9, Efna1, Rac1, Rras, Ascl2, Tfap2c, Prl7b1) in FGR placentas, with a reduction in CK8 trophoblast staining. Angiogenesis reduction in FGR was demonstrated with reduced Vegfa, Vegfb, and Akt3 and supported by reduced CD31, CD105, and VEGF2 endothelial cell markers A caloric-restriction mouse model replicates key FGR pathophysiology, including reduced fetal/placental growth, downregulation of trophoblast invasion genes, impaired trophoblast invasion into the decidua, and reduced placenta angiogenesis. These findings offer molecular insights into placental insufficiency that merits further exploration regarding FGR pathogenesis.
