College of Marine Science and Fisheries, Jiangsu Ocean University, Lianyungang, 222005, Jiangsu, China.
Toxicology and Food Contaminants Department, Food Industries and Nutrition Research Institute, National Research Centre, Dokki, P.O. Box 12622, Giza, Egypt.
Environ Sci Pollut Res Int. 2024 Mar;31(15):23077-23090. doi: 10.1007/s11356-024-32441-8. Epub 2024 Feb 28.
The contamination of toxic heavy metals in aquatic environments has garnered significant global attention due to its detrimental effects on marine organisms and human health. Hexavalent chromium is a typical environmental and occupational heavy metal pollutant, identified as carcinogenic heavy metal. This study aimed to assess the impact of different Cr (VI) concentrations (0.05-2.5 mg/L) on Urechis unicinctus (U. unicinctus) by investigating bioaccumulation, antioxidant defense system, expression of resistance-related genes, and histological issues. A clear concentration-effect relationship was observed in the bioaccumulation of Cr (VI) in muscle tissues of U. unicinctus. Moreover, exposure to Cr (VI) can alter the activities of lysozyme (LSZ), catalase (CAT), and superoxide dismutase (SOD) to enhance cellular defense mechanisms in U. unicinctus. Likewise, maintained the normal protein structure and functional stability by regulating protein folding. The heat shock cognitive protein (HSC70) gene showed an upward and then downward trend after Cr (VI) exposure. At 12 h, the HSC70 gene expression reached the maximum values of 4.75 and 4.61-fold in the 0.1 and 1.5 mg/L groups, respectively. The organism produced a large number of free radicals, and elevated level of metallothionein (MT) was used to scavenge free radicals and alleviate oxidative stress. Additionally, histopathological examination revealed disorganization in the midgut, atrophic changes in intestinal connective tissue, uneven distribution in respiratory tissues, and irregular shape with a significant reduction in epithelial cells within the gastric cavity. These findings can serve as a valuable reference for elucidating the toxicity mechanisms of heavy metals towards marine benthic organisms and enhancing water environment monitoring strategies.
水生环境中有毒重金属的污染引起了全球的广泛关注，因为它对海洋生物和人类健康有很大的危害。六价铬是一种典型的环境和职业重金属污染物，被认为是致癌重金属。本研究旨在评估不同浓度的六价铬（0.05-2.5 mg/L）对单环刺螠（Urechis unicinctus）的影响，通过研究生物蓄积、抗氧化防御系统、抗性相关基因的表达和组织学问题来进行评估。在单环刺螠肌肉组织中，六价铬的生物蓄积呈现出明显的浓度-效应关系。此外，暴露于六价铬会改变溶菌酶（LSZ）、过氧化氢酶（CAT）和超氧化物歧化酶（SOD）的活性，以增强单环刺螠的细胞防御机制。同样，通过调节蛋白质折叠来维持正常的蛋白质结构和功能稳定性。热休克认知蛋白（HSC70）基因在暴露于六价铬后呈现出先上升后下降的趋势。在 12 h 时，HSC70 基因在 0.1 和 1.5 mg/L 组中的表达分别达到最大值，为 4.75 和 4.61 倍。机体产生大量自由基，金属硫蛋白（MT）水平升高，用于清除自由基和减轻氧化应激。此外，组织病理学检查显示中肠组织紊乱、肠结缔组织萎缩、呼吸组织分布不均匀、胃腔上皮细胞形状不规则且明显减少。这些发现可以为阐明重金属对海洋底栖生物的毒性机制提供有价值的参考，并增强水环境监测策略。
