Department of Fisheries and Aquaculture, Alex Ekwueme Federal University Ndufu Alike Ikwo, Nigeria; Department of Zoology, University of Nigeria Nsukka, Nigeria.
Department of Zoology, University of Nigeria Nsukka, Nigeria.
Comp Biochem Physiol C Toxicol Pharmacol. 2020 Jun;232:108741. doi: 10.1016/j.cbpc.2020.108741. Epub 2020 Mar 11.
The aquatic environment is outrageously littered with resin pellets and particles of plastic origin which can jeopardise the health of aquatic organisms. The present study investigated the effect of polyvinyl chloride (PVC) microparticles on blood parameters, leucocytes, lipid peroxidation and antioxidant system (brain and gill) of Clarias gariepinus. C. gariepinus is a fresh water indicator species often used as model for ecotoxicological assay. Fish specimens were exposed to diets spiked with PVC microparticles (95.41 ± 4.23 μm) at the following concentrations; 0.50%, 1.50% and 3.0% and control diet for 45 days, followed by a depuration trial which lasted for 30 days. Blood and tissues (brain and gill) were sampled every 15 days interval for haematology, antioxidant enzymes and lipid peroxidation assay. The result obtained revealed that PVC orchestrated the marked alterations in haematological indices. Mean cell volume and mean cell haemoglobin values reduced significantly in all concentration treated groups and were time-dependent. Neutrophil counts decreased with a corresponding increase in PVC exposure time while lymphocytes and monocytes values showed no significant difference between the control and exposed fish groups. Glutathione peroxidase activity was altered substantially in the brain and gill of the exposed groups compared to the control. Superoxide dismutase activity was inhibited in the brain and gill of the exposed groups compared to the control, as well as the different exposed periods. Catalase activity reduced significantly in the brain of 0.5% PVC exposed groups, and also decreased in a time-dependent manner while its activity in the gill did not change significantly among the exposed groups relative to the control. Lipid peroxidation levels in the brain of PVC exposed groups increased significantly in a dose and time-dependent manner. However, PVC caused no significantly change in the gill lipid peroxidation level of the exposed fish, but elevated the lipid peroxidation levels as the exposure time increased. Acetylcholinesterase activity in the brain and gill of the exposed fish reduced substantially with increase in the exposure time. Variations in haematology, antioxidant enzymes, lipid peroxidation and acetylcholinesterase activities are indicative of oxidative stress and neurotoxicity in fish. C. gariepinus is an indispensable bioindicator to measure environmental impact of PVC microparticles.
水生环境中充斥着大量的树脂颗粒和塑料颗粒，这些颗粒可能会对水生生物的健康造成危害。本研究调查了聚氯乙烯 (PVC) 微颗粒对蓝鳃太阳鱼血液参数、白细胞、脂质过氧化和抗氧化系统（大脑和鳃）的影响。蓝鳃太阳鱼是一种淡水指示物种，常用于生态毒理学检测模型。将鱼暴露于添加 PVC 微颗粒（95.41±4.23μm）的饮食中，浓度分别为 0.50%、1.50%和 3.0%，并以对照饮食作为空白对照，进行为期 45 天的暴露实验，然后进行为期 30 天的净化实验。每隔 15 天采样一次血液和组织（大脑和鳃），进行血液学、抗氧化酶和脂质过氧化检测。结果表明，PVC 显著改变了血液学指标。所有浓度处理组的平均红细胞体积和平均红细胞血红蛋白值均显著降低，且呈时间依赖性。中性粒细胞计数随着暴露时间的延长而降低，而淋巴细胞和单核细胞值在对照组和暴露组之间没有显著差异。与对照组相比，暴露组大脑和鳃中的谷胱甘肽过氧化物酶活性显著改变。与对照组相比，暴露组大脑和鳃中的超氧化物歧化酶活性受到抑制，不同暴露期也受到抑制。对照组大脑中的过氧化氢酶活性显著降低，且呈时间依赖性，而其在鳃中的活性在暴露组之间没有显著变化。暴露组大脑中的脂质过氧化水平显著升高，呈剂量和时间依赖性。然而，暴露组对鱼鳃中的脂质过氧化水平没有显著影响，但随着暴露时间的增加，脂质过氧化水平升高。暴露组大脑和鳃中的乙酰胆碱酯酶活性显著降低，随着暴露时间的增加而降低。血液学、抗氧化酶、脂质过氧化和乙酰胆碱酯酶活性的变化表明鱼类存在氧化应激和神经毒性。蓝鳃太阳鱼是衡量 PVC 微颗粒对环境影响的不可或缺的生物指标。
