Tissue Harvesting

Mice were anesthetized with CO₂/O₂ on gd 13.5 or 18.5, respectively. A blood sample was collected by retro bulbar puncture and subsequently mice were sacrificed by cervical dislocation. The harvested uterus-draining lymph node was kept in PBS on ice. The fetuses and corresponding placentas were isolated from the amniotic membranes. After assessment of fetal weight, fetuses were fixed with Bouin’s solution. The empty uterus was stored in HBSS on ice. Placentas were either stored at -20°C in RNAlater (Ambion by Life Technologies GmbH) for subsequent gene expression analysis or embedded in biopsy cassettes and stored in 4% Formaldehyde solution (36.5-38%, Sigma-Aldrich, St, Louis, US) for 24 h before transfer into 1% Formaldehyde solution for long-term storage and histological staining.