To examine the alteration in cellular characteristics of polyploid embryonic stem (ES) cells during long-term culturing without leukemia inhibitory factor (LIF), mouse diploid and tetraploid H-1 (ES) cells (2H1 and 4H1 cells, respectively) were cultured without LIF for approximately 5 months. 2H1 and 4H1 cells were adapted to the medium without LIF by decreasing the concentration for several passages, and they were denoted as 2H1⁽⁻⁾ and 4H1⁽⁻⁾ cells, respectively. DNA content of 4H1⁽⁻⁾ cells decreased gradually in the early stage, increased abruptly in the second stage, and then was maintained for a long time. 4H1⁽⁻⁾ cells exhibited longer doubling time and equivalent phase fraction compared with those of 2H1⁽⁻⁾ cells. The G₁ phase fractions of 2H1⁽⁻⁾ and 4H1⁽⁻⁾ cells were increased compared with that of 2H1 cells. Cellular morphology and pluripotency were maintained in 4H1⁽⁻⁾ cells but not in 2H1⁽⁻⁾ cells. 2H1⁽⁻⁾ cells showed a cell population consisting of several kinds of cells, and they lost alkaline phosphatase activity, suggesting that the cells had differentiated. 4H1⁽⁻⁾ cells, however, exhibited alkaline phosphatase activity and formed teratocarcinoma in mouse abdomen, suggesting that the cells maintained their pluripotency in the medium without LIF.

中文翻译：

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在不含白血病抑制因子的 L15F10 培养基中长期培养二倍体和四倍体 H1 胚胎干细胞时出现不同的反应。

为了检查在没有白血病抑制因子 (LIF) 的情况下长期培养过程中多倍体胚胎干 (ES) 细胞的细胞特征的变化，在没有使用白血病抑制因子 (LIF) 的情况下培养小鼠二倍体和四倍体 H-1 (ES) 细胞（分别为 2H1 和 4H1 细胞） LIF 大约 5 个月。2H1 和 4H1 细胞通过降低几代的浓度来适应不含 LIF 的培养基，它们分别表示为 2H1 ^(-)和 4H1 ^(-)细胞。4H1 ^(-)细胞的DNA含量在早期逐渐减少，在第二阶段突然增加，然后长期保持。与 2H1 ^(-)相比，4H1 ^(-)细胞表现出更长的倍增时间和等效相位分数细胞。与 2H1 细胞相比，2H1 ^(-)和 4H1 ^(-)细胞的 G ₁期分数增加。细胞形态和多能性在 4H1 ^(-)细胞中保持，但在 2H1 ^(-)细胞中没有。2H1 ^(-)细胞显示出由多种细胞组成的细胞群，并且它们失去了碱性磷酸酶活性，表明细胞已经分化。然而，4H1 ^(-)细胞表现出碱性磷酸酶活性并在小鼠腹部形成畸胎瘤，表明细胞在没有 LIF 的培养基中保持其多能性。