Journal of Xenobiotics

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.

Genetic polymorphisms can modulate susceptibility to mercury (Hg) toxicity by altering metabolic and detoxification pathways. This review evaluated the association between genetic variants, Hg exposure, and obstetric outcomes. A systematic search of Scopus, PubMed and ScienceDirect through May 2025 identified 12 eligible studies (n = 4995), conducted in accordance with PRISMA guidelines, with methodological quality assessed using the Newcastle–Ottawa Scale. Meta-analysis was selectively performed only for genetically and methodologically comparable studies. The most frequently examined genes were GSTP1, GCLC, GCLM, GPX1, MT1A, ALAD, and APOE. Meta-analysis of GSTP1 rs1695, showed no statistically significant association between the Val105 allele and hair mercury concentrations (MD = −0.08 µg/g; 95% CI: −0.18 to 0.02; p = 0.13), although the direction of effect suggested a potential protective trend. Polymorphisms in other glutathione-related genes (GCLC, GCLM, and GPX1) were consistently associated with increased risks of small-for-gestational-age infants, preeclampsia, and impaired neurodevelopmental outcomes in offspring. In contrast, the APOE ε4 allele appeared to be associated with reduced fetal mercury burden, whereas polymorphisms in ALAD and MT1A were linked to higher mercury levels and adverse pregnancy-related outcomes. By integrating epidemiological evidence with mechanistic insights within a gene–environment interaction framework, this review helps to address important gaps in the existing literature. These findings underscore the importance of incorporating genetic susceptibility into Hg risk assessment and precision-based prenatal interventions.

The central mechanistic hypothesis underlying multifactorial hearing loss posits that genetic susceptibility and environmental exposures act synergistically to disrupt cochlear homeostasis through redox imbalance, mitochondrial dysfunction, and pro-inflammatory mechanisms. This gene–environment paradigm has significant translational implications: elucidating the molecular crosstalk between genetic variants and environmental factors may enable precision risk stratification and the development of targeted otoprotective strategies. The present review provides a comprehensive examination of the major determinants implicated in hearing loss. The manuscript is organized into six main sections that encompass the most relevant domains of current research. First, it offers (I) an overview of epidemiological patterns and the multifactorial nature of hearing impairment. This is followed by (II) a background synthesis of the complex genetic architecture underlying hearing loss. Next, the authors present (III) an outline of environmental determinants and exposure profiles associated with auditory dysfunction, highlighting prominent pollutant/xenobiotic classes (e.g., organic solvents and volatile aromatic hydrocarbons, heavy metals, pesticides, and especially organophosphates and persistent organochlorine compounds), followed by (IV) an analysis of oxidative stress, mitochondrial impairment, and inflammatory pathways involved in cochlear injury. Subsequently, (V) translational perspectives and integrated therapeutic approaches are discussed, with emphasis on epidemiological prevention and precision-based interventions. Finally, (VI) this review addresses current challenges and future directions in elucidating gene–environment interactions in hearing loss.