Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Science Campus 6(th) Floor, Alagappa University, Karaikudi 630004, Tamil Nadu, India.
Biomaterials and Biotechnology in Animal Health Lab, Department of Animal Health and Management, Science Campus 6(th) Floor, Alagappa University, Karaikudi 630004, Tamil Nadu, India; Marine College, Shandong University, Weihai 264209, PR China.
Comp Biochem Physiol C Toxicol Pharmacol. 2021 Dec;250:109161. doi: 10.1016/j.cbpc.2021.109161. Epub 2021 Aug 8.
Effect of selenium and acidification in freshwater environment was assessed solitary but no reports are available on the impacts of both factors act together. In the present study, effects of combined simultaneous exposure to selenium (Se) and low pH were assessed in Mozambique tilapia, Oreochromis mossambicus. Responses were measured based on antioxidant defenses (enzymatic SOD, CAT, GPx and non-enzymatic GSH), biotransformation enzyme (GST), metallothionein levels (MT), oxidative damage (LPO, CP), Na/K-ATPase (NKA) activity in gills and liver tissues and neurotoxicity (acetylcholinesterase, AChE) response in brain tissue. Fish were exposed to combined treatment at different pH levels (7.5, control (optimum pH for tilapia growth); 5.5, low pH) and Se concentrations (0, 10, and 100 μg L). Toxicity levels of Se were not significantly different under control and low pH indicating that pH did not affect Se toxicity. Levels of GSH and MT were enhanced in Se-exposed fish at both pH. Combined effects of high Se concentration and low pH decreased SOD and CAT activities and increased those of GPx and GST. However, organisms were not able to prevent cellular damage (LPO and CP), indicating a condition of oxidative stress. Furthermore, inhibition of Na/K-ATPase activity was showed. Additionally, neurotoxicity effect was observed by inhibition of cholinesterase activity in organisms exposed to Se at both pH conditions. As a result, the combined stress of selenium and freshwater acidification has a slight impact on antioxidant defense mechanisms while significantly inhibiting cholinesterase and Na+/K + -ATPase activity in fish. The mechanisms of freshwater acidification mediating the toxic effects of trace non-metal element on freshwater fish need to investigate further.
在淡水环境中评估了硒和酸化的单独作用，但尚无关于这两个因素共同作用的影响的报道。在本研究中，评估了同时暴露于硒 (Se) 和低 pH 值对莫桑比克罗非鱼 Oreochromis mossambicus 的联合影响。根据抗氧化防御（酶 SOD、CAT、GPx 和非酶 GSH）、生物转化酶（GST）、金属硫蛋白水平（MT）、氧化损伤（LPO、CP）、鳃和肝脏组织中的 Na/K-ATPase (NKA) 活性以及脑组织中的神经毒性（乙酰胆碱酯酶，AChE）反应来测量反应。鱼在不同的 pH 值水平（7.5，对照（罗非鱼生长的最适 pH 值）；5.5，低 pH 值）和 Se 浓度（0、10 和 100μg L）下暴露于联合处理中。在对照和低 pH 值下，硒的毒性水平没有显著差异，表明 pH 值不影响硒的毒性。在 Se 暴露的鱼中，GSH 和 MT 的水平均升高。高 Se 浓度和低 pH 值的联合作用降低了 SOD 和 CAT 活性，增加了 GPx 和 GST 活性。然而，机体无法防止细胞损伤（LPO 和 CP），表明处于氧化应激状态。此外，还显示出 Na/K-ATPase 活性受到抑制。此外，在两种 pH 值条件下暴露于 Se 的生物体中，通过抑制胆碱酯酶活性观察到神经毒性作用。结果表明，硒和淡水酸化的联合胁迫对抗氧化防御机制有轻微影响，而显著抑制鱼类中胆碱酯酶和 Na+/K+ -ATPase 活性。需要进一步研究淡水酸化介导痕量非金属元素对淡水鱼类毒性作用的机制。
