Chen Fan, Luo An-Feng, Pan Kai-Xin, Gu Hao, Zhou Chang-Fan, Zeng Wei, Liu Song, Molenaar Adrian, Ren Hong-Yan, Huo Li-Jun, Bi Yan-Zhen
Key Laboratory of Animal Embryo Engineering and Molecular Breeding of Hubei Province, Institute of Animal Sciences and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430070, China.
Key Laboratory of Animal Embryo Engineering and Molecular Breeding of Hubei Province, Institute of Animal Sciences and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430070, China; Rumen Microbiology and Animal Nutrition and Physiology AgResearch, Grasslands Campus, Fitzherbert Research Centre, Palmerston North 4410, New Zealand.
Ecotoxicol Environ Saf. 2025 Jan 1;289:117595. doi: 10.1016/j.ecoenv.2024.117595. Epub 2025 Jan 10.
3-methyl-4-nitrophenol (PNMC), a chemical prevalent in various industries for drug, dye, and leather production, also serves as a primary byproduct of organophosphate insecticides. Despite its global recognition as an endocrine disruptor with documented reproductive toxicity, its detrimental impact on preimplantation embryonic development has yet to be thoroughly investigated. In this study, through the in vitro culture of mice embryos, it was initially observed that even low concentrations of PNMC exposure led to a significant reduction in blastocyst formation and a sharp decline in the ratio of inner cell mass within the blastocysts. SMART-seq2 transcriptome sequencing further confirmed that PNMC treatment disrupted global gene expression in 2-cell embryos, with differentially expressed genes enriched in multiple signaling pathways, including those related to autophagy, apoptosis, fertilization, embryonic development, transcription, and mRNA processing. Integration of transcriptome data with open databases revealed that both zygotic genome activation genes and maternal factors experienced significant transcript-level disruptions. Moreover, the study demonstrated that these gene expression changes were closely associated with mitochondrial dysfunction, evidenced by diminished mitochondrial membrane potential, reduced ATP production, aberrant expression of mitochondria-related genes, increased ROS accumulation, and heightened DNA damage in PNMC-treated embryos. Additionally, PNMC exposure induced defects in histone modification, as shown by altered levels of H3K9me3 and H3K27me3, H3K9ac and H3K27ac. Lastly, the findings indicated that PNMC triggered apoptosis in embryos, validated by elevated BAX and CASPASE3 expression, alongside positive TUNEL staining. In summary, PNMC exposure impairs the maternal-to-zygotic transition, likely through mitochondrial dysfunction and histone modification, culminating in developmental arrest and apoptosis in mouse preimplantation embryos.
3-甲基-4-硝基苯酚（PNMC）是一种在药物、染料和皮革生产等多个行业中普遍存在的化学物质，也是有机磷杀虫剂的主要副产物。尽管它作为一种具有生殖毒性记录的内分泌干扰物已得到全球认可，但其对植入前胚胎发育的有害影响尚未得到充分研究。在本研究中，通过对小鼠胚胎进行体外培养，最初观察到即使低浓度的PNMC暴露也会导致囊胚形成显著减少以及囊胚内细胞团比例急剧下降。SMART-seq2转录组测序进一步证实，PNMC处理会破坏2-细胞胚胎中的整体基因表达，差异表达基因富集于多个信号通路，包括与自噬、凋亡、受精、胚胎发育、转录和mRNA加工相关的通路。将转录组数据与开放数据库整合后发现，合子基因组激活基因和母体因子在转录水平上均受到显著破坏。此外，该研究表明这些基因表达变化与线粒体功能障碍密切相关，PNMC处理的胚胎中线粒体膜电位降低、ATP产生减少、线粒体相关基因表达异常、ROS积累增加以及DNA损伤加剧均证明了这一点。此外，PNMC暴露还诱导了组蛋白修饰缺陷，表现为H3K9me3和H3K27me3、H3K9ac和H3K27ac水平的改变。最后，研究结果表明PNMC会引发胚胎凋亡，BAX和CASPASE3表达升高以及TUNEL染色阳性证实了这一点。总之，PNMC暴露可能通过线粒体功能障碍和组蛋白修饰损害母体向合子的转变，最终导致小鼠植入前胚胎发育停滞和凋亡。
