【摘要】 以ＳＴＯ细胞和鼠胚原代成纤维细胞（ＰＭＥＦ）为饲养层建立了１１个小鼠胚胎于细胞系（ＥＳ细胞系）。两种饲养层细胞都可以维持ＥＳ细胞的正常形态和体外分化能力，但ＳＴＯ细胞不能维持ＥＳ细胞的正常二倍体核型，ＰＭＥＦ的效果比ＳＴＯ为佳，但也仅能短期内维持二倍体状态，１０代后染色体数目逐渐发生偏离。分离出１０个ＥＳ细胞克隆。讨论了两种饲养层的不同和影响核型发生偏离的若干可能的原因。更多还原

【Abstract】 mouse embryonic stem (ES)cell lines have been established by usingthe feeder Layer of the STO cells or the primary mouse embrvonic fibroblasts(PMEF).ES cells on both kinds of feeders could maintain the stem一cell-like mor-phologyand could differentiate into embryoid bodies in suspension culture. But theES cells on STO feeder cell layer could not retain the normal diploid karyotype,only15%of ES cells of MESPU 3/12(the 12th subculture of ES cell line MESPU 3)were diploid and MESPU 9/7 had only 5%diploid ES cells,PMEF had a better ef-fect than STO,however it could function only in a short period.The chromosomenumber gradualy dispersed after 10th subculture of ES cells with PMEF feeder,e.g. ES cell line MESPU 11 had diploid karyotype of 73%and 77%after 6th and 9thsubculture respectively,but the number of normal karyotype reduced to 64%in theMESPU 11/12 and were even less in MESPU 11/20 ,which was only 15%. Ten EScolonies were picked out. The differences between the two kinds of feeder layers andthe possible reasons which may cause the variation of karyotype were discussed.更多还原