Rasta Majid, Kakakhel Mian Adnan, Taleshi Mojtaba S, Lashkaryan Niloofar S, Manke Jia, Liu Liming, Soomro Shan-E-Hyder, Shi Xiaotao
College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang, Hubei 443002, China.
Department of Marine Chemistry, Faculty of Marine and Oceanic Sciences, University of Mazandaran, Babolsar, Iran.
Ecotoxicol Environ Saf. 2025 Sep 1;302:118596. doi: 10.1016/j.ecoenv.2025.118596. Epub 2025 Jul 1.
Recently, concerns about the toxicity of microplastics (MPs) pollution have attracted significant attention. However, the influence of hydrodynamics on MPs bioaccumulation in fish, and the associated risks, remains poorly understood. Therefore, this study addressed this critical knowledge gap by examining how water velocity, individual and in combination with MPs, impacts brain in juvenile grass carp (Ctenopharyngodon idella). Fish were exposed for seven days (28 h total, with 2-h sessions twice daily) to 5 µm polystyrene MPs (PS-MPs) at an environmentally relevant concentration of 1000 µg/L across eight groups: control, low (LV), medium (MV), and high (HV) water velocity, MPs-only, and three combined treatments (MPs + each velocity level). Fish exposed to the MPs + HV group illustrated the highest accumulation of PS-MPs with a concentration of 33.94 ± 1.00 × 10 μg/kg (p < 0.05) and exhibited more brain damage, including hemorrhage, edema, and tissue rupture. Furthermore, this group demonstrated significantly increased superoxide dismutase (SOD) and lipid peroxidation (LPO) activities, along with significant reduction in acetylcholinesterase (AChE) activity (p < 0.05), providing clear evidence of oxidative stress and neurotoxicity. Transcriptomic analysis showed a significant variation in gene expression with associated key pathways such as DNA repair, RNA transport, FoxO signaling, and MAPK signaling, indicating active cellular responses to genetic damage. Overall, this study highlighted the critical role of hydrodynamics in MPs bioaccumulation in fish and the compounded risks of MPs and water velocity, emphasizing the crucial need for monitoring of MPs pollution in dynamic aquatic environments, particularly in riverine systems.
最近，对微塑料（MPs）污染毒性的担忧引起了广泛关注。然而，水动力对鱼类体内MPs生物累积的影响以及相关风险仍知之甚少。因此，本研究通过考察水流速度、单独及与MPs共同作用时如何影响草鱼幼鱼（Ctenopharyngodon idella）的大脑，填补了这一关键的知识空白。将鱼暴露于环境相关浓度1000μg/L的5μm聚苯乙烯微塑料（PS-MPs）中7天（共28小时，每天两次，每次2小时），分为八组：对照组、低（LV）、中（MV）、高（HV）水流速度组、仅MPs组以及三种联合处理组（MPs + 各水流速度水平）。暴露于MPs + HV组的鱼体内PS-MPs累积量最高，浓度为33.94±1.00×10μg/kg（p < 0.05），且表现出更多的脑损伤，包括出血、水肿和组织破裂。此外，该组超氧化物歧化酶（SOD）和脂质过氧化（LPO）活性显著增加，同时乙酰胆碱酯酶（AChE）活性显著降低（p < 0.05），这为氧化应激和神经毒性提供了明确证据。转录组分析显示基因表达存在显著差异，涉及DNA修复、RNA转运、FoxO信号通路和MAPK信号通路等相关关键途径，表明细胞对遗传损伤有活跃的反应。总体而言，本研究强调了水动力在鱼类MPs生物累积中的关键作用以及MPs与水流速度的复合风险，强调了在动态水生环境，特别是河流系统中监测MPs污染的迫切需求。
