Culture of rabbit embryonic germ cells derived from primordial germ cells

Primordial germ cells (PGCs) were developed as new material for isolation and cloning of embryonic stem (ES) cells, which were designated as embryonic germ cells (EG) to distinguish their tissue origin. The collected PGCs were cultured on feeder layers obtained from mitotically inactivated mouse or rabbit fibroblasts in Dulbecco's modified Eagle's medium supplemented with soluble recombinant human leukemia inhibitory factor (20 ng/ml), stem cell factor (30 ng/ml), forskolin (20 ng/ml). Two stable undifferentiated EG cell lines were established and were passed to fresh feeders every week for maintenance of their undifferentiated state. The established EG cell lines were pluripotent and were capable of forming embryonic bodies which differentiated into varied cell types including autorhythmic cells without efficient feeder layers. By comparison of growth behaviors of EG cells, we found that homogenous are superior to heterogenous fetal fibroblast feeder layers to support the EG growth.