Phthalate esters (PAEs) raised serious concerns on their health risk due to their toxicities. However, toxicities of low-molecular-weight PAEs, for example, dimethyl phthalates (DMPs), remained poorly investigated. In the present study, the reproductive toxicities of dimethyl (o-)phthalate (DMOP), dimethyl (p-)phthalate (DMPP), and dimethyl (m-)phthalate (DMMP) were measured on Caenorhabditis elegans with mechanical exploration. Results showed that DMPP, DMOP, and DMMP commonly inhibited the total reproduction while stimulated lifespan, showing trade-off effects. In effects on gene expressions, DMPP, DMOP, and DMMP caused different regulations on the expressions of vab-1, ceh-18, and gsa-1 which are involved in oocyte growth, ovulation, and maturation. Meanwhile, they commonly downregulated those of rme-2 and rcy-4 that regulate germ cells and gonads and lipid metabolism in oocytes. Moreover, the effects on biochemicals that regulate reproductive processes showed alteration between stimulation and inhibition over life stages. In addition, effects at apical, biochemical, and molecular levels clearly showed the structure influences on the toxicities. Summing up, reproductive toxicities of DMPs depended on the exposure life stages and also the chemical structures.

中文翻译：

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邻苯二甲酸二甲酯对秀丽隐杆线虫的生殖毒性以及整个生命阶段反应的变化

邻苯二甲酸酯（PAE）因其毒性而引发了对其健康风险的严重关注。然而，低分子量 PAE，例如邻苯二甲酸二甲酯 (DMP) 的毒性仍然缺乏研究。在本研究中，通过机械探查测量了（邻）邻苯二甲酸二甲酯（DMOP）、（对）邻苯二甲酸二甲酯（DMPP）和（间）邻苯二甲酸二甲酯（DMMP）对秀丽隐杆线虫的生殖毒性。结果表明，DMPP、DMOP 和 DMMP 普遍抑制总繁殖，同时刺激寿命，呈现出权衡效应。在对基因表达的影响方面，DMPP、DMOP和DMMP对参与卵母细胞生长、排卵和成熟的vab-1、ceh-18和gsa-1的表达产生不同的调节。同时，它们通常下调调节卵母细胞生殖细胞和性腺以及脂质代谢的rme-2和rcy-4 。此外，对调节生殖过程的生化物质的影响显示出在生命阶段刺激和抑制之间的变化。此外，顶端、生化和分子水平的影响清楚地显示了结构对毒性的影响。综上所述，DMP 的生殖毒性取决于接触生命阶段和化学结构。