Kawase Eihachiro, Shirayoshi Yasuaki, Hashimoto Koichiro, Nakatsuji Norio
Mammalian Development Laboratory, National Institute of Genetics, 1111 Yata, Mishima 411, Japan.
Division of Developmental Biology, Meiji Institute of Health Science, 540 Naruda, Odawara 250, Japan.
Dev Growth Differ. 1996 Jun;38(3):315-322. doi: 10.1046/j.1440-169X.1996.t01-2-00011.x.
Recent studies have shown that stem cell factor (SCF), leukemia inhibitory factor (LIF), basic fibroblast growth factor (bFGF) and the enhancement of cAMP levels increase proliferation and survival of mouse primordial germ cells (PGC) in vitro. Even after the addition of these factors, however, it is still not possible to obtain proliferation of PGC at a rapid rate similar to that in vivo, suggesting the presenge of other growth factor(s) in vivo. We previously reported that tumor necrosis factor-α stimulates proliferation of PGC at earlier migration stages. We now show that the use of SI/SI4-m220 feeder cells and the addition of a medium conditioned with Buffalo rat liver cells and forskolin to the culture medium stimulate PGC obtained from 8.5 days post coitum embryos to proliferate in culture at a rate comparable to that in vivo. Under such conditions, proliferation of PGC continued several days past the timing of growth arrest in vivo; however, it did stop afterwards. Such proliferating PGC continue to express c-kit and Oct-3 proteins. The characteristics of the culture medium and the requirement of feeder cells were different from those for embryonic stem (ES) cells, suggesting that these rapidly proliferated PGC are not transformed into ES-like EG cells.
最近的研究表明，干细胞因子（SCF）、白血病抑制因子（LIF）、碱性成纤维细胞生长因子（bFGF）以及cAMP水平的提高可增加小鼠原始生殖细胞（PGC）在体外的增殖和存活。然而，即便添加了这些因子，仍无法使PGC以类似于体内的快速速率增殖，这表明体内存在其他生长因子。我们之前报道过肿瘤坏死因子-α可刺激处于早期迁移阶段的PGC增殖。我们现在表明，使用SI/SI4-m220饲养细胞并向培养基中添加经布法罗大鼠肝细胞和福斯可林处理过的条件培养基，可刺激从交配后8.5天胚胎中获取的PGC在培养中以与体内相当的速率增殖。在这种条件下，PGC的增殖在体内生长停滞时间之后还持续了数天；不过，之后确实停止了。这种增殖的PGC继续表达c-kit和Oct-3蛋白。培养基的特性和饲养细胞的需求与胚胎干细胞（ES）不同，这表明这些快速增殖的PGC并未转化为类似ES的EG细胞。
