Simple and highly efficient method for transient in vivo gene transfer to mid-late pregnant mouse uterus

Up- and down-regulation of various genes in the placenta, decidua and amnion has been reported during the mid-late period of pregnancy and in pregnancy-related complications, such as preeclampsia and preterm labor. However, whether this gene regulation at the feto-maternal interface directly influences the physiology/pathophysiology of disease remains unknown. In order to study this problem, transient gene transfer into the pregnant uterus at mid-late term would be a useful tool. We injected exogenous plasmid entrapped using a commercially available Hemagglutinating Virus of Japan Envelope (HVJ-E) vector system (GenomONE Neo, Ishihara Sangyo) into the extra-amniotic space of the upper part of the pregnant mouse uterus on day 14.5 post-coitus (p.c.). Luciferase activity driven by the cytomegalovirus promoter was detectable for 3 days after transfection in the upper, middle and lower part of the uterus. β-Galactsidase activity was localized in the basal lamina of the placenta, the decidual membrane and the fetal membrane. Exogenous plasmid was not transmitted to the fetus. The course of pregnancy was not disturbed by this procedure; rupture of membranes, intrauterine fetal growth restriction and preterm birth were not observed. Thus, we demonstrated that this transient gene transfer method is highly efficient and minimally invasive, and expect that this procedure will be a useful tool to analyze the pathophysiology of pregnancy-related disorders.