College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China; College of Life and Environmental Sciences, Hunan University of Arts and Science, Changde 415000, China; Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China.
College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
Sci Total Environ. 2023 Dec 15;904:166830. doi: 10.1016/j.scitotenv.2023.166830. Epub 2023 Sep 4.
Microcystin-LR (MC-LR) produced by cyanobacteria blooms poses a serious risk to aquatic organisms. Rice straw-derived biochar (BC) is gradually being utilized as an effective adsorbent to remove water pollutants. In the present study, the combined toxicity of MC-LR and BC on hepatic antioxidant capacity and metabolic phenotype of zebrafish (Danio rerio) were conducted due to the increasing concern of eutrophication in aquatic environments. Female zebrafish were exposed to solutions of MC-LR (10 μg/L) and BC (100 μg/L) individually and in combination for 30 days. The results indicated that sub-chronic MC-LR exposure induced oxidative stress and metabolic disorders, with a significant elevation of several amino acids, glucose as well as unsaturated fatty acids. Metabolic pathway analysis showed that the ascorbate and aldarate metabolism and biosynthesis of unsaturated fatty acids were affected under MC-LR stress. Significantly increased MDA levels along with significantly decreased CAT and GPx activities were observed in the MC-LR group. Nevertheless, MDA levels, antioxidant enzyme activities, and the relevant gene expressions (cat1, nrf2a, HO-1, keap1a) returned to baseline in the co-exposure group. These findings revealed that MC-LR resulted in metabolic disorders of protein, sugar, and lipid related to energy production, and BC could relieve MC-LR-induced metabolic disorder and oxidative stress in the liver of zebrafish. However, the potential risk of BC-induced metabolic disorder should not be neglected. Our present results highlight the potential of BC as a tool for mitigating the negative impacts of MC-LR on aquatic organisms in blooms-contaminated water.
微囊藻毒素-LR（MC-LR）是由水华蓝藻产生的，对水生生物构成严重威胁。稻秆衍生生物炭（BC）作为一种有效去除水污染物的吸附剂，正逐渐得到应用。由于对富营养化水环境污染的日益关注，本研究探讨了 MC-LR 和 BC 联合毒性对斑马鱼（Danio rerio）肝抗氧化能力和代谢表型的影响。将雌性斑马鱼分别暴露于 10μg/L MC-LR 和 100μg/L BC 溶液中，以及同时暴露于这两种溶液中，为期 30 天。结果表明，亚慢性 MC-LR 暴露可诱导氧化应激和代谢紊乱，导致多种氨基酸、葡萄糖和不饱和脂肪酸水平显著升高。代谢通路分析显示，在 MC-LR 胁迫下，抗坏血酸和醛糖代谢以及不饱和脂肪酸的生物合成受到影响。MC-LR 组 MDA 水平显著升高，CAT 和 GPx 活性显著降低。然而，在共暴露组中，MDA 水平、抗氧化酶活性和相关基因表达（cat1、nrf2a、HO-1、keap1a）均恢复至基线水平。这些发现表明，MC-LR 导致与能量产生相关的蛋白质、糖和脂质代谢紊乱，BC 可缓解 MC-LR 诱导的斑马鱼肝代谢紊乱和氧化应激。然而，不应忽视 BC 引起的代谢紊乱的潜在风险。本研究结果强调了 BC 作为减轻富营养化水华污染水域中 MC-LR 对水生生物负面影响的一种工具的潜力。
