90 and 96 hours embryos were plated on ME(mouse embryonic fibroblast cells)feeder layer, using DMEM/F12 medium with 10% FBS and 10%rabbit serum supplemented with LIF or EGF.

• 建系条件为，使用小鼠原始胚胎成纤维细胞（ME）作饲养层，以含10%25胎牛血清和10%25兔血清的DMEM/F12为培养基，添加白血病抑制因子（LIF）或上皮生长因子（EGF），胚龄为90，96h。