Mouse fetuses in late gestation maintained in vitro by a transplacental perfusion method and their physiological activities.

The present study demonstrated that live mouse fetuses in late gestation can be kept in vitro and their physiological activities maintained for over 24 h. Fetuses together with uterus were isolated from pregnant mice at 11.5-17.5 days gestation and transplacentally perfused with a physiological solution through a cannula inserted into the uterine artery. Under these conditions, various physiological activities including heartbeats and spontaneous and stimulation-induced fetal movements were observed.