Bifenthrin (BF) is a synthetic insecticide that is widely used in fields, resulting in an increase in its exposure to animals. However, reports on the toxic effects of BF on mammalian species and the underlying mechanism are still lacking. Here, we elucidated the mechanism underlying the toxic effects of BF on mouse reproduction using cell lines of immature mouse Leydig (TM3) and Sertoli (TM4) cells, which are constituent cells of testes. Our results show that BF suppressed the proliferation and viability of TM3 and TM4 cells. Additionally, treatment with BF induced cell cycle arrest, apoptotic cell death, and DNA fragmentation. Mitochondrial dysfunction and disruption of calcium homeostasis were observed in BF-treated TM3 and TM4 cells. Further, bifenthrin modulated unfolded protein response and mitochondrion-associated membrane and mitogen-activated protein kinase (MAPK)/phosphoinositide 3-kinase (PI3K) signaling pathways. The expression of the mRNAs related to cell cycle progression, steroidogenesis, and spermatogenesis was downregulated by BF, suggestive of testicular toxicity. Taken together, these results demonstrate the intracellular mechanism of action of BF to involve antiproliferative and apoptotic effects and testicular dysfunction in mouse testis.

联苯菊酯（BF）是一种合成杀虫剂，广泛用于田野，导致其与动物的接触增加。但是，仍然缺乏关于高炉对哺乳动物物种的毒性作用及其潜在机制的报道。在这里，我们阐明了使用未成熟小鼠Leydig（TM3）和Sertoli（TM4）细胞（它们是睾丸的组成细胞）的细胞系，BF对小鼠生殖产生毒性作用的潜在机制。我们的结果表明，BF抑制了TM3和TM4细胞的增殖和活力。此外，用BF处理可诱导细胞周期停滞，凋亡细胞死亡和DNA断裂。在BF处理的TM3和TM4细胞中观察到线粒体功能障碍和钙稳态的破坏。进一步，联苯菊酯调节未折叠的蛋白应答和线粒体相关的膜和丝裂原激活的蛋白激酶（MAPK）/磷酸肌醇3激酶（PI3K）信号通路。BF下调了与细胞周期进程，类固醇生成和精子生成相关的mRNA表达，提示睾丸毒性。综上所述，这些结果证明了BF的细胞内作用机制涉及小鼠睾丸的抗增殖和凋亡作用以及睾丸功能障碍。