Faculty of Marine Science and Technology, Iskenderun Technical University, P.O. Box: 31200, Iskenderun, Hatay, Turkey.
Faculty of Arts and Sciences, Hatay Mustafa Kemal University, P.O. Box: 31060, Antakya, Hatay, Turkey.
Ecotoxicology. 2020 Nov;29(9):1522-1537. doi: 10.1007/s10646-020-02253-w. Epub 2020 Jul 24.
One of the major problems affecting the ecosystem health is the exposure of heavy metals due to anthropogenic activities. These exposures may induce toxiogenetic damage and carcinogenesis in aquatic organism. DNA damage biomarkers for fish species detect genotoxic parameters for ecological risk assessment. In the present study, the effect of heavy metals (Cr, Cd, Cu, Fe and Mn) on DNA damage and oxidative stress of Clarias gariepinus was examined by Comet assay at Reference site and two different sampling sites of the Orontes River. Moreover, the relationship between DNA damage and physiological response to oxidative stress caused in C. gariepinus was investigated by sampling seasonal water and fish samples for one year. In this study, Cr, Cd and Cu in water column of Orontes River and the concentrations of Fe and Mn in liver tissue of C. gariepinus were highly exceed the maximum permissible limit set by EPA (1999, 2016) WHO (1989) and TEG (2012) that can cause adverse effects on environment health. SOD activities in liver tissues were significantly higher than those in muscle tissues. SOD, CAT activity and MDA levels of both Site 1 and Site 2 at Orontes River were higher than those of the Reference site. In result of the COMET analysis, the highest levels of DNA damage were found at gill and liver tissues in Site 2 (17.746 ± 1.072% T-DNA; 16.014 ± 0.710% T-DNA respectively) at Orontes river. A higher level of DNA damage in gill cells compared to liver cells was observed in all regions of the Orontes River. In Principal component analysis (PCA), the heavy metals Cd, Cr and Cu (in the water column) and MDA in liver and muscle revealed strong contribution to the observed DNA damage that were scattered opposite to each other's along the principal components. Moreover, correlations between parameters revealed a positive significant relationship between Cd, Cr and Cu in water and DNA damage levels in C. gariepinus. Pearson correlation analysis detected a positive relationship between MDA, CAT and SOD and DNA damage levels in African catfish. Consequently, this study exposed genotoxic damage and oxidative stress of C. gariepinus due to metal pollution in Orontes River and lead to the better understanding of genotoxicty, oxidative stress and heavy metal relationships.
一个影响生态系统健康的主要问题是由于人为活动导致重金属暴露。这些暴露可能会在水生生物中引起致病变和致癌作用。鱼类物种的 DNA 损伤生物标志物可检测生态风险评估的遗传毒性参数。在本研究中，通过彗星试验研究了重金属（Cr、Cd、Cu、Fe 和 Mn）对奥龙特斯河参考点和两个不同采样点的蓝鲶 DNA 损伤和氧化应激的影响。此外，通过对奥龙特斯河的季节性水样和鱼类样本进行为期一年的采样，研究了 DNA 损伤与蓝鲶氧化应激生理反应之间的关系。在本研究中，奥龙特斯河水柱中的 Cr、Cd 和 Cu 以及蓝鲶肝脏组织中的 Fe 和 Mn 浓度均远高于 EPA（1999 年，2016 年）、世界卫生组织（1989 年）和 TEG（2012 年）规定的最大允许限值，这些物质会对环境健康造成不良影响。肝脏组织中的 SOD 活性明显高于肌肉组织。奥龙特斯河的 1 号和 2 号采样点的 SOD、CAT 活性和 MDA 水平均高于参考点。彗星分析结果表明，奥龙特斯河 2 号采样点（鳃组织：17.746±1.072% T-DNA；肝脏组织：16.014±0.710% T-DNA）的 DNA 损伤水平最高。在奥龙特斯河的所有区域均观察到鳃细胞的 DNA 损伤水平高于肝细胞。主成分分析（PCA）表明，重金属 Cd、Cr 和 Cu（在水柱中）以及肝脏和肌肉中的 MDA 对观察到的 DNA 损伤有很强的贡献，它们沿着主成分彼此相反地分布。此外，参数之间的相关性表明，奥龙特斯河水中的 Cd、Cr 和 Cu 与蓝鲶的 DNA 损伤水平之间呈正相关关系。Pearson 相关性分析检测到 MDA、CAT 和 SOD 与蓝鲶 DNA 损伤水平之间呈正相关关系。因此，本研究暴露了奥龙特斯河金属污染对蓝鲶的遗传毒性损伤和氧化应激，并使我们更好地了解遗传毒性、氧化应激和重金属之间的关系。
