纳米银对胚胎细胞基因表达谱的影响和毒性机制

目的：利用基因芯片技术考察纳米银对大鼠胚胎细胞基因表达谱的影响，分析其毒性作用的分子机制。方法：胚胎细胞在20 μg·mL^-1纳米银/细胞培养液混悬液内暴露48 h，提取细胞RNA，利用基因芯片技术对受试细胞的基因表达谱和未经纳米银处理的对照组细胞进行对比分析，考察受试细胞的基因表达谱变化。结果：纳米银引起了胚胎细胞总差异表达基因数为355个，其中上调基因132个，下调基因223个;显著地激活了免疫系统相关的自然杀伤细胞介导的毒性、B细胞受体信号通路等生物学反应;抑制了蛋白质氨基酸磷酸化生物学过程；诱导了分泌型白细胞肽酶抑制因子和基质金属蛋白酶3（MMP3）等基因表达的显著增高。结论：纳米银通过激活免疫系统相关的信号通路引起了胚胎细胞广泛的生物学反应;胚胎细胞通过上调分泌型白细胞肽酶抑制因子等来抵御纳米银所引起的刺激和损伤;纳米银抑制了蛋白质氨基酸磷酸化生物学过程，诱导了胚胎细胞MMP3的显著高表达，从而可能造成细胞各种生物学功能的障碍和细胞基质的严重破坏。胚胎细胞不同于癌化细胞株或其他不死化细胞，更接近人体正常细胞的功能和特性。这些新的毒性机制的发现对正确地理解纳米银对正常人体的潜在毒性风险有着非常重要的意义;同时有助于更好地理解纳米银的生殖毒性风险。

Objective: To investigate the effects of silver nanoparticles(silver NPs)on the gene expression profile of rat embryo cells,and to further analyze the molecular mechanisms of silver-NP-induced toxicity. Methods: Embryo cells were treated with 20 μg·mL^-1 silver NPs suspension(suspended in cell culture medium)for 48 hours,and then the RNAs were extracted.The gene expression profile of treated cells was analyzed compared to the control cells using DNA microarray technology. Results: Totally 355 differentially expressed genes which were induced by silver NPs were observed.Among them,132 of the genes were up-regulated,and 223 of the genes were down-regulated.Some biological responses related to the immune system were significantly activated,such as natural killer cell mediated cytotoxicity and B cell receptor signaling pathway.The biological process of phosphorylation of protein amino acids was inhibited.The secretory leukocyte peptidase inhibition factor and MMP3 etc.were increased significantly. Conclusion: Silver NPs induced global biological responses of embryo cells through activating some signal pathways,such as inflammatory and immune system related signal pathways.Embryonic cells protected themselves against injury and damage caused by silver NPs with upregulating secretory leukocyte peptidase inhibitor,etc.Silver NPs inhibited the biological process of protein amino acid phosphorylation and induced the high expression of MMP3,which might further decrease various biological functions of the cells and cause serious damage to the cell matrix.In contrast to cancer cell lines or other immortal cells,embryo cells have much similar functions and properties to normal human cells.These new toxic mechanisms found in silver NPs exposed normal cells are very important for understanding the potential toxicity of silver NPs to humans.The present finding also contributes to a better understanding of the reproductive toxicity risks of silver NPs for medical applications.