Polycyclic aromatic hydrocarbons (PAHs) accumulate and integrate into aquatic environments, raising concerns about the well-being and safety of aquatic ecosystems. Benzo[a]pyrene (BaP), a persistent PAH commonly detected in the environment, has been extensively studied. However, the broader multifaceted toxicity potential of BaP on the early life stages of marine fish during chronic exposure to environmentally relevant concentrations needs further exploration. To fill these knowledge gaps, this study assessed the biotoxicity of BaP (1, 4, and 8 μg/L) in marine medaka () during early development over a 30-day exposure period. The investigation included morphological, biochemical, and molecular-level analyses to capture the broader potential of BaP toxicity. Morphological analyses showed that exposure to BaP resulted in skeletal curvatures, heart anomalies, growth retardation, elevated mortality, delayed and reduced hatching rates. Biochemical analyses revealed that BaP exposure not only created oxidative stress but also disrupted the activities of antioxidant enzymes. This disturbance in redox balance was further explored by molecular level investigation. The transcriptional profiles revealed impaired oxidative phosphorylation (OXPHOS) and tricarboxylic acid (TCA) cycle pathways, which potentially inhibited the oxidative respiratory chain in fish following exposure to BaP, and reduced the production of adenosine triphosphate (ATP) and succinate dehydrogenase (SDH). Furthermore, this investigation indicated a potential connection to apoptosis, as demonstrated by fluorescence microscopy and histological analyses, and supported by an increase in the expression levels of related genes via real-time quantitative PCR. This study enhances our understanding of the molecular-level impacts of BaP's multifaceted toxicity in the early life stages of marine medaka, and the associated risks.

中文翻译：

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长期暴露于环境浓度的苯并[a]芘会导致海洋青鳉（Oryzias melastigma）生命早期阶段的发育受损、氧化还原失衡和转录谱调节等多方面的毒性作用


多环芳烃 (PAH) 会积累并融入水生环境，引发人们对水生生态系统福祉和安全的担忧。苯并[a]芘 (BaP) 是一种在环境中常见的持久性多环芳烃，已得到广泛研究。然而，在长期暴露于环境相关浓度的过程中，BaP 对海洋鱼类早期生命阶段的更广泛的多方面毒性潜力需要进一步探索。为了填补这些知识空白，本研究评估了海洋青鳉 () 在 30 天暴露期内的早期发育过程中 BaP（1、4 和 8 μg/L）的生物毒性。该研究包括形态学、生化和分子水平分析，以捕捉 BaP 毒性的更广泛潜力。形态学分析表明，接触 BaP 会导致骨骼弯曲、心脏异常、生长迟缓、死亡率升高、孵化率延迟和降低。生化分析表明，BaP 暴露不仅会产生氧化应激，还会破坏抗氧化酶的活性。通过分子水平研究进一步探讨了氧化还原平衡的这种干扰。转录谱显示氧化磷酸化 (OXPHOS) 和三羧酸 (TCA) 循环途径受损，这可能会抑制接触 BaP 后鱼类的氧化呼吸链，并减少三磷酸腺苷 (ATP) 和琥珀酸脱氢酶 (SDH) 的产生。此外，如荧光显微镜和组织学分析所证明的那样，这项研究表明与细胞凋亡的潜在联系，并通过实时定量 PCR 相关基因表达水平的增加得到了支持。 这项研究增强了我们对 BaP 多方面毒性对海洋青鳉生命早期阶段的分子水平影响以及相关风险的理解。