Diflubenzuron Caused Mitochondrial Dysfunction, Ca ²⁺ Homeostasis Disruption, and Intrinsic Apoptosis in Trophoblastic Cells

Diflubenzuron is used as an insect growth inhibitor, and its potential risk to human health was raised owing to the possibility of environmental residues and human exposure. This study aimed to investigate the toxic mechanism of diflubenzuron on trophoblastic cells such as HTR8/SVneo and JEG-3 cells. We investigated mitochondrial function, Ca²⁺ homeostasis, and expression of associated genes following diflubenzuron exposure (0, 1, 2, and 3 μg/mL). In addition, apoptosis induction, cell cycle arrest, and migration ability were evaluated. Diflubenzuron treatment induced a loss of mitochondrial membrane potential, disruption of Ca²⁺ homeostasis, and upregulation of endoplasmic reticulum stress markers such as IRE1α and GRP78. Furthermore, intrinsic apoptosis was triggered by BAX and BAK upregulation and BCL2 downregulation. Cell cycle arrest in the G₀/G₁ phase was induced, and the migration ability of trophoblastic cells was significantly reduced by diflubenzuron treatment. These alterations suggest that mitochondrial dysfunction with the downregulation of hormone receptors (progesterone receptor and estrogen receptor 1 and 2) may impair trophoblastic function. This study confirmed that diflubenzuron has a cytotoxic effect on trophoblastic cells and may impair trophoblastic functions related to implantation. Collectively, these results highlight the potential of diflubenzuron as a reproductive toxicant in disrupting early pregnancy processes. Further studies are needed to clarify exposure relevance and to evaluate potential risks to human reproductive health.