Aluminium (Al) is soluble in acidic waters and may become toxic to organisms. In this study, the acute effects of two Al concentrations were evaluated in the Amazonian fish Bryconops caudomaculatus. Antioxidant responses and lipid damage were assessed in gills, liver and muscle, along with the electrocardiography (ECG) and characterization of cardiac complex and wave intervals. Fish were essayed as follows: two control groups at neutral and acidic pH and two exposure groups at acidic pH (0.3 mg/L and 3.0 mg/L Al). Water samples were collected at 0h, 24h and 48h, for chloride (Cl⁻), fluoride (F⁻) and sulphate (SO₄²⁻) ion analyses, while total Al was quantified in muscle. Concentrations of Cl⁻ and SO₄²⁻ were constant over time whereas F⁻ was not detected. Total Al concentrations in water and muscle were concentration-dependent. Antioxidant responses, total antioxidant capacity against peroxyl radicals (ACAP) and glutathione S-transferase were not triggered in fish tissues exposed to 0.3 mg/L Al; however, fish exposed to 3.0 mg/L Al presented increased and reduced ACAP in gills and liver, respectively. No changes in lipoperoxidation levels occurred among groups. Fish exposed to 0.3 mg/L Al showed prolonged intervals in ECG as a reflection of low heart rate (HR), with sinus bradycardia. Moreover, there was a marked prolongation of the PQ interval (time between the atrial activity and the start of ventricular activity), indicating interference on the cardiac cell automaticity. Fish exposed to the highest concentration of Al showed reduced wave intervals as a consequence of increased HR, with sinus arrhythmia, while ECG tracings did not present P waves (atrial contraction), indicating an atrioventricular blockade. In conclusion, 48h exposure sufficed to cause cardiotoxicity in B. caudomaculatus at either Al concentration. However, as oxidative stress was not observed, such cardiac alterations seem to be reversible under the experimental conditions established herein.

铝 (Al) 可溶于酸性水中，可能对生物体有毒。在这项研究中，在亚马逊鱼Bryconops caudomaculatus中评估了两种 Al 浓度的急性影响。评估了鳃、肝脏和肌肉中的抗氧化反应和脂质损伤，以及心电图 (ECG) 和心脏复合体和波间期的表征。鱼的分析如下：中性和酸性 pH 值的两个对照组和酸性 pH 值（0.3 mg/L 和 3.0 mg/L Al）的两个暴露组。在 0 小时、24 小时和 48 小时收集水样，用于氯化物 (Cl ^- )、氟化物 (F ^- ) 和硫酸盐 (SO ₄ ^2- ) 离子分析，同时对肌肉中的总铝进行量化。Cl的浓度^-和 SO ₄ ^2-随着时间的推移是恒定的，而 F ^-没有被检测到。水和肌肉中的总铝浓度是浓度依赖性的。在暴露于 0.3 mg/L Al 的鱼组织中，没有触发抗氧化反应、抗过氧自由基 (ACAP) 和谷胱甘肽 S-转移酶的总抗氧化能力；然而，暴露于 3.0 mg/L Al 的鱼的鳃和肝脏中的 ACAP 分别增加和减少。各组之间没有发生脂过氧化水平的变化。暴露于 0.3 mg/L Al 的鱼在 ECG 中表现出延长的间隔，作为低心率 (HR) 的反映，并伴有窦性心动过缓。此外，PQ 间期（心房活动和心室活动开始之间的时间）显着延长，表明对心脏细胞自律性的干扰。暴露于最高浓度 Al 的鱼由于 HR 增加而显示波间期缩短，伴有窦性心律失常，而 ECG 描记未出现 P 波（心房收缩），表明房室传导阻滞。总之，暴露 48 小时足以引起心脏毒性B. caudomaculatus在任一 Al 浓度下。然而，由于没有观察到氧化应激，因此在本文建立的实验条件下，这种心脏改变似乎是可逆的。