Dose- and Time-dependent Histopathological and Immunotoxic Effects of DEHP on the Spleen of Sparidentex hasta: Implications for Fish Health and Veterinary Toxicology

Introduction: This study comprehensively evaluated the dose- and time-dependent effects of di-(۲-ethylhexyl) phthalate (DEHP), a widely used environmental contaminant, on the spleen of Sparidentex hasta over a ۱۴-day exposure period.  Materials & Methods: Fish were exposed to five concentrations of DEHP (۰, ۵, ۱۰, ۵۰, and ۱۰۰ µg/g), and splenic responses were assessed through quantitative morphometric indices, including spleen weight (SW), spleen somatic index (SSI), and spleen-to-length ratio (SLR), as well as qualitative histopathological analysis. Statistical comparisons were performed using SPSS ۲۶, and graphical representations were generated in Excel.Results: Results demonstrated significant dose- and time-related increases in SW (۰.۱۰ g in controls vs ۰.۲۷ g at ۱۰۰ µg/g, P<۰.۰۵), SSI (۰.۰۸۹% vs ۰.۲۷۶%, P<۰.۰۵), and SLR (۰.۵۶۳% vs ۱.۶۹۸%, P<۰.۰۵). Histopathological examinations revealed progressive structural alterations with increasing DEHP concentrations, including sinusoidal congestion, lymphocytic hyperplasia, melanomacrophage center (MMC) accumulation, and focal necrosis. Lower doses induced mild adaptive responses, whereas higher exposures resulted in pronounced tissue disorganization and immune activation. Strong correlations between morphometric indices and microscopic lesions suggested that splenic enlargement reflects both oxidative stress and immunotoxic effects.  Conclusion: These findings underscore the sensitivity of the spleen as a reliable biomarker for detecting sublethal immunotoxicity in fish exposed to environmental pollutants. Overall, this study highlights the importance of integrating quantitative indices with histopathological evaluation to assess the ecotoxicological impacts of DEHP, providing valuable insights for environmental monitoring, fish health management, and aquaculture sustainability. The results further emphasize the potential ecological and economic consequences of DEHP contamination in aquatic ecosystems.

کلیدواژه ها:

Diethylhexyl phthalate (DEHP) ، Fish diseases ، Histology ، Immunotoxicity ، Spleen pathology ، Toxicology