Developmental toxicity and mechanistic insights of tralopyril in marine medaka: Epigenetic disruptions and ferroptosis

Tralopyril has emerged as a promising alternative to the banned tributyltin in marine antifouling applications. However, its ecological risks remain underestimated. Through an integrated approach combining behavioral phenotyping, transcriptomics, and whole-genome bisulfite sequencing (WGBS), we demonstrate that tralopyril (0, 1, 10 μg/L) disrupts marine medaka ( Oryzias melastigma) development via two interrelated mechanisms: (1) Epigenetic dysregulation: Aberrant CG methylation in key regulatory genes ( casr , cacna2d2 , dnai1 , alox15b , etc.) was associated with developmental toxicity, altering gene expression profiles critical for normal growth. (2) Ferroptosis activation: Tralopyril exposure triggered iron overload and fth1 dysregulation, while mitochondrial uncoupling ( ucp2 ) exacerbated oxidative stress, contributing to cellular damage. Notably, epigenetic alterations, such as methylation changes in alox15b , can influence the ferroptosis pathway by regulating genes involved in iron metabolism and oxidative stress. This, in turn, amplified toxic effects and contributed to multiorgan damage. These alterations led to defects such as cardiac remodeling, skeletal malformations, and neuromuscular dysfunction, ultimately resulting in locomotor decline. Inhibitor rescue experiments identified critical molecular targets of tralopyril's toxic effects and demonstrated cross-regulation between ucp2 expression and the ferroptosis pathway. These findings elucidate the key molecular mechanisms underlying tralopyril-induced developmental abnormalities and behavioral impairments, emphasizing the synergistic effects of mitochondrial dysfunction and ferroptosis. Overall, this study expands the understanding of mitochondrial function and ferroptosis in environmental toxicology and provides a scientific basis for ecological risk assessment and mitigation strategies for environmental pollutants. • Tralopyril caused multiple tissue damage, resulting in decreased swimming behavior. • DNA methylation was involved in the regulation of developmental toxicity. • Ferroptosis inhibitors rescue locomotor deficits, offering mitigation strategies. • Potential indicator genes may be mmp13 , ucp2 , fth1 .