Maharajan Kannan, Muthulakshmi Sellamani, Nataraj Bojan, Ramesh Mathan, Kadirvelu Krishna
DRDO-BU Center for Life Sciences, Bharathiar University Campus, Coimbatore, India.
Unit of Toxicology, Department of Zoology, Bharathiar University, Coimbatore, India.
Aquat Toxicol. 2018 Mar;196:132-145. doi: 10.1016/j.aquatox.2018.01.010. Epub 2018 Jan 12.
Pyriproxyfen (2-[1-methyl-2-(4-phenoxyphenoxy) ethoxy] pyridine) (PPF), a pyridine-based pesticide widely used to control agricultural insect pests and mosquitoes in drinking water sources. However, its ecotoxicological data is limited in aquatic vertebrates particularly in fish. Hence, the present study aimed to evaluate the adverse effect of PPF in zebrafish embryo development (Danio rerio). In order to investigate the impact of PPF, embryos were exposed to 0.16, 0.33 and 1.66 μg/mL (0.52, 1.04 and 5.2 μM, respectively) for 96 hpf and various biomarker indices such as developmental toxicity (edema formation, hyperemia, heart size and scoliosis), oxidative stress (reactive oxygen species (ROS), lipid peroxidation (LPO) and nitric oxide (NO)), antioxidant responses (superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione peroxidase (GPx) and reduced glutathione (GSH)), biochemical (lactate dehydrogenase (LDH) and acid phosphatase (AP)), neurotoxicity (acetylcholinesterase (AChE)), genotoxicity (apoptosis and DNA damage) and histopathological changes were determined. The results showed that severe developmental deformities and changes in heart rate were observed in embryos treated with highest (1.66 μg/mL) concentration than the control (P < 0.05). Heart size measurement showed that, significant change in heart size (P < 0.01) was observed in embryos of 96 hpf only at 1.66 μg/mL PPF exposure. The oxidative stress was apparent at highest test concentration (1.66 μg/mL) as reflected by the elevated ROS, LPO and NO and changes in antioxidant enzyme activities including SOD, CAT, GST and GPx (P < 0.05). Besides, GSH level and AChE activity were significantly lowered in 1.66 μg/mL PPF exposed group than the control. After 96 hpf of PPF exposure, no significant changes were found in AP activity whereas, a biphasic response was observed in the LDH activity. There was no genotoxic effect in embryos exposed to PPF at 0.16 and 0.33 μg/mL, while significant (P < 0.05) DNA damage and apoptosis were found in 1.66 μg/mL treated group. Histopathological analysis revealed that exposure to PPF at 1.66 μg/mL resulted in thinning of heart muscles, pericardial edema and hyperemia while there was no obvious changes were observed in other treatment groups. Hence, the results of the present study demonstrate that PPF could cause adverse effect on early developmental stages of zebrafish at higher concentration.
吡丙醚（2-[1-甲基-2-(4-苯氧基苯氧基)乙氧基]吡啶）（PPF）是一种吡啶类农药，广泛用于控制农业害虫和饮用水源中的蚊子。然而，其生态毒理学数据在水生脊椎动物尤其是鱼类中有限。因此，本研究旨在评估PPF对斑马鱼胚胎发育（斑马鱼）的不利影响。为了研究PPF的影响，将胚胎暴露于0.16、0.33和1.66μg/mL（分别为0.52、1.04和5.2μM）96小时，测定各种生物标志物指标，如发育毒性（水肿形成、充血、心脏大小和脊柱侧凸）、氧化应激（活性氧（ROS）、脂质过氧化（LPO）和一氧化氮（NO））、抗氧化反应（超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽S-转移酶（GST）、谷胱甘肽过氧化物酶（GPx）和还原型谷胱甘肽（GSH））、生化指标（乳酸脱氢酶（LDH）和酸性磷酸酶（AP））、神经毒性（乙酰胆碱酯酶（AChE））、遗传毒性（凋亡和DNA损伤）以及组织病理学变化。结果表明，与对照组相比，用最高浓度（1.66μg/mL）处理的胚胎出现了严重的发育畸形和心率变化（P<0.05）。心脏大小测量显示，仅在1.66μg/mL PPF暴露下，96小时胚胎的心脏大小有显著变化（P<0.01）。氧化应激在最高测试浓度（1.66μg/mL）时明显，表现为ROS、LPO和NO升高以及抗氧化酶活性变化，包括SOD、CAT、GST和GPx（P<0.05）。此外，1.66μg/mL PPF暴露组的GSH水平和AChE活性显著低于对照组。PPF暴露96小时后，AP活性无显著变化，而LDH活性呈双相反应。在0.16和0.33μg/mL PPF暴露的胚胎中未发现遗传毒性作用，而在1.66μg/mL处理组中发现了显著的（P<0.05）DNA损伤和凋亡。组织病理学分析显示，1.66μg/mL PPF暴露导致心肌变薄、心包水肿和充血，而其他处理组未观察到明显变化。因此，本研究结果表明，PPF在较高浓度下可能对斑马鱼的早期发育阶段产生不利影响。
