Screening for embryonic loss during in utero development of mice with a human 1.5 Tesla clinical MRI scanner

Abstract

To establish in utero MRI-scanning of mouse implantation sites in a 1.5 Tesla whole-body human clinical scanner for evaluation of impaired implantation, placental or developmental defects due to genetic alterations. Pregnant C57Bl/6 wild-type and Cx31-deficient mice revealing placental defects were analyzed in utero using a 1.5 Tesla whole-body clinical scanner in combination with a 3-cm-diameter single loop (slice thickness: 1.2 mm). Imaging of implantation sites was evaluated from 6.5-13.5 dpc and amount of implantation sites and in vivo development was analyzed during the critical phase of placentation from 10.5-13.5 dpc. This method provided high resolution in plane images permitting confident identification of all implantation sites from 6.5 dpc onward. A loss of 60% of Cx31-deficient embryos was demonstrated compared with controls. Repeated anesthesia as well as imaging protocols produced no gross malformations in the surviving mice. Using a human clinical MRI scanner high resolution imaging of the entire uterus of the mice and all the embryos inside could be performed. This method is well suited to noninvasively monitor and quantify embryo implantation and to follow this dynamic process in vivo without compromising pregnancy progression and embryonic development.