邻苯二甲酸单乙基己基酯对小鼠胚胎干细胞多能性相关转录因子表达的影响

Effects of mono(2-ethylhexyl)phthalate on pluripotency-related transcription factors of mouse embryonic stem cells

[目的]研究邻苯二甲酸单乙基己基酯(MEHP)对小鼠胚胎干细胞多能性维持能力的影响。[方法]不同浓度的MEHP(0、0.1、1、10、100、1 000μmol/L)处理小鼠胚胎干细胞(m ESCs)4 d,观察细胞形态,采用流式细胞术检测细胞凋亡指标;应用碱性磷酸酶染色法、real-time PCR及Western blot分别检测其分化情况、胚胎干细胞多能性相关转录因子SOX2、OCT4基因及其蛋白表达水平。[结果]随着MEHP染毒浓度的增加,m ESCs克隆的细胞团逐渐缩小,且数量也出现减少,以1 000μmol/L组尤为明显;细胞凋亡检测结果发现,随着染毒浓度增加,凋亡率呈增加趋势,与对照组相比,仅1 000μmol/L组m ESCs总细胞凋亡率[(9.58±2.02)%]的升高有统计学意义(P<0.05)。碱性磷酸酶染色结果显示,1 000μmol/L组m ESCs着色较浅,甚至未着色,即出现分化倾向,而其他组m ESCs均被染成深蓝色或蓝紫色。与对照组相比,100、1 000μmol/L组中SOX2、OCT4基因表达降低(均P<0.05);1 000μmol/L组SOX2、OCT4蛋白表达降低(均P<0.05)。[结论]一定浓度MEHP对m ESCs存在细胞毒性,抑制m ESCs正常生长,降低m ESCs中多能性相关转录因子SOX2、OCT4的表达,进而影响胚胎早期发育。

[Objective] To investigate the effect of mono（2-ethylhexyl）phthalate （MEHP） on pluripotency-related transcription factors of mouse embryonic stem cells （mESCs）.[Methods] Designed concentrations of MEHP （0, 0.1, 1, 10, 100, and 1 000 μmol/L, respectively） were administered to mESCs for 4 d. Cell morphology was observed and cell apoptosis was detected by flow cytometry. The differentiation of mESCs was detected by alkaline phosphatase staining. The expressions of pluripotency-related transcription factors SOX2 and OCT4 genes and proteins in embryonic stem cells were detected by real-time PCR and Western blot respectively.[Results] With the increase of exposure dose, the clonal cell clusters of mESCs were shrunk and cell count reduced, especially in the 1 000 μmol/L MEHP group; compared with the control group, the apoptosis rate of mESCs rised with increasing concentration and only elevated significantly in the 1 000μmol/L MEHP group[（9.58±2.02）%] （P 〈 0.05）. Alkaline phosphatase staining revealed that the mESCs in the 1 000 μmol/L group were lighter or even not stained, indicating differentiation tendency, while the cells in other groups were dyed dark blue or blueviolet. Compared with the control group, the SOX2 and OCT4 gene expressions in the 100 and 1 000 μmol/L groups decreased （Ps 〈 0.05）, and the SOX2 and OCT4 protein expressions in the 1 000 μmol/L group decreased （Ps 〈 0.05）.[Conclusion] MEHP at certain concentrations is cytotoxic to mESCs, inhibits mESCs growth, and decreases the expressions of pluripotency-related transcription factors SOX2 and OCT4 in mESCs, which may affect early development of embryos.