Journal of Xenobiotics

Background: Human exposure to endocrine-disrupting chemicals (EDCs) is increasingly linked to male reproductive dysfunction, but underlying mechanisms remain unclear. This study aimed to evaluate how selected pharmacological (dihydroxyflutamide, 2OH-FTA; bicalutamide, BIC) and agrochemical (lindane, βHCH; permethrin, PERM; mancozeb, MNZ; tributyltin oxide, TBTO) EDCs affect mitochondrial function in human spermatozoa with parameters within World Health Organization (WHO) reference ranges. Methods: Human sperm cells were exposed ex vivo to 0.1–1000 nM of each compound. Mitochondrial respiration was measured using polarography, assessing oxygen consumption in active (V₃) and resting (V₄) states, and the respiratory control ratio (RCR) was calculated as an index of mitochondrial coupling. Results: Both 2OH-FTA and BIC reduced RCR in a concentration-dependent manner, mainly due to increases in V₄, with BIC showing the strongest effect. βHCH produced a similar pattern, elevating V₄ and decreasing RCR. In contrast, PERM, MNZ, and TBTO caused near-complete collapse of both V₃ and V₄ even at sub-nanomolar concentrations, indicating severe, concentration-independent mitochondrial toxicity. Conclusions: Sperm mitochondria are highly sensitive to EDCs, and distinct compounds exert different bioenergetic effects. Mitochondrial respiration assays provide a useful tool for ex vivo toxicological screening and risk assessment.

A significant and persistent issue in assisted reproduction is recurrent implantation failure (RIF), which is often observed even after the transfer of embryos of high morphological and/or genetic quality. Accumulating data suggest that exposure to chemicals with endocrine-disrupting effects (EDCs) may be associated with adverse implantation outcomes. Many environmentally widespread substances have the potential to interfere with the regulation of the endocrine system, affecting critical mechanisms involved in implantation, such as endometrial receptivity, steroid hormone receptor signaling, immune tolerance at the maternal–fetal interface, and the epigenetic regulation of genes that are essential for successful implantation. Experimental studies have shown that exposure to EDCs can alter gene expression in the endometrium, inflammatory pathways, and the dynamics of early embryonic development, while clinical and epidemiological data have associated increased levels of EDCs in the body with lower implantation rates in assisted reproductive technology (ART) cycles. This narrative review examines the implications of these findings in reproductive medicine, summarizes recent experimental and clinical data, and highlights the molecular mechanisms linking exposure to endocrine disruptors with recurrent implantation failure. Recognizing environmental chemical exposure as a potentially modifiable risk factor may offer new perspectives for the prevention of RIF and the development of more personalized therapeutic strategies.

Oxidative and nitrosative stress are central mechanisms in the pathogenesis of neurodegenerative diseases, where excessive production of reactive oxygen and nitrogen species (ROS/RNS) leads to mitochondrial dysfunction, membrane damage, and neuronal death. In this study, we established and compared short-term (2 h) and long-term (20 h) exposure paradigms to sodium nitroprusside (SNP), used as a xenobiotic nitric oxide donor, in two neuronal cell lines (mHippoE-18 and PC12) and zebrafish larvae, aiming to provide a preclinical framework for neurodegenerative drug discovery. In vitro, SNP exposure caused concentration-dependent reductions in viability and alterations in oxidative balance, with mHippoE-18 cells exhibiting higher susceptibility than PC12 cells. In the short-term exposure paradigm, cytotoxicity was primarily associated with membrane disruption at higher concentrations, whereas oxidative stress contributed more strongly at intermediate doses. In the long-term exposure, mHippoE-18 cells showed strong integrated correlations between ROS, LDH release, and viability loss, highlighting their increased vulnerability to nitrosative stress. In zebrafish, SNP exposure impaired metabolic activity and swimming behavior in both paradigms. Long-term exposure led to consistent dose-dependent increases in ROS, accompanied by locomotor deficits tightly linked to energy metabolism. Overall, the higher sensitivity of mHippoE-18 cells compared with PC12 cells, together with the dose-dependent metabolic and behavioral impairments observed in zebrafish, indicates that cellular responses partially mirror in vivo outcomes. This integrative approach underscores the value of combining neuronal cell lines with zebrafish larvae to capture complementary aspects of SNP-induced neurotoxicity and to strengthen preclinical evaluation of candidate compounds with protective or therapeutic potential. These findings support the use of SNP as a xenobiotic model to probe nitrosative stress-driven neurotoxicity across cellular and organismal systems.