Ciprofloxacin drugs are a second-generation fluoroquinolone highly prescribed medication against various bacterial infections in human and aquaculture practices. These drugs are chemically designed to persist in the body long enough to achieve target objectives. Extensive usage has resulted in ciprofloxacin becoming a ubiquitous contaminant in the environment. Unfortunately, the ecotoxicological profiles for ciprofloxacin are scanty. This study was aimed to assess the ecotoxicity of ciprofloxacin at environmentally relevant concentrations (1 μg/L, and 1.5 μg/L) to a cultivable fish Cirrhinus mrigala. Responses of antioxidant enzymes, histological anomalies, and inorganic ion levels were studied. SOD activity in gill, liver, and kidney tissues was elevated in ciprofloxacin-exposed groups when compared with the control group. CAT activity was predominantly decreased in ciprofloxacin treated groups relative to the control group. GST activity in the ciprofloxacin treated groups was increased (except kidney tissues [Treatment I (1 μg/L)], and gill tissues fifteenth day) significantly (p < .05). The LPO level was elevated in the ciprofloxacin treatment groups throughout the study period (except Treatment II (1.5 μg/L) tenth day in kidney tissues). A series of histological anomalies were noticed in the gill, liver, and kidney tissues of the ciprofloxacin treated groups. Ciprofloxacin exposure caused a significant decrease of sodium, potassium, and chloride levels in the plasma of C. mrigala. A parallel among an imbalanced oxidative defense system, tissue structural changes, and alterations of plasma inorganic ions could be considered as a reliable biomarker for antibiotic toxicity study. This study could be a primary platform for further toxicity studies to understand the potential molecular impacts and adverse effects of ciprofloxacin on aquatic organisms.

中文翻译：

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Cirrhinus mrigala 对第二代氟喹诺酮（环丙沙星）毒性的反应：抗氧化剂、组织形态和无机离子的评估

环丙沙星药物是第二代氟喹诺酮类药物，用于对抗人类和水产养殖实践中的各种细菌感染。这些药物经过化学设计，可以在体内持续足够长的时间以达到目标。广泛使用导致环丙沙星成为环境中普遍存在的污染物。不幸的是，环丙沙星的生态毒理学资料很少。本研究旨在评估环丙沙星在环境相关浓度（1 μg/L 和 1.5 μg/L）下对可养殖鱼 Cirrhinus mrigala 的生态毒性。研究了抗氧化酶的反应、组织学异常和无机离子水平。与对照组相比，环丙沙星暴露组的鳃、肝脏和肾脏组织中的 SOD 活性升高。与对照组相比，环丙沙星治疗组的 CAT 活性显着降低。环丙沙星治疗组的 GST 活性显着增加（除肾组织 [治疗 I (1 μg/L)] 和第 15 天的鳃组织）显着增加 (p < .05)。在整个研究期间，环丙沙星治疗组的 LPO 水平升高（除了治疗 II (1.5 μg/L) 第 10 天在肾组织中）。在环丙沙星治疗组的鳃、肝和肾组织中观察到一系列组织学异常。环丙沙星暴露导致 C. mrigala 血浆中钠、钾和氯化物水平显着降低。氧化防御系统失衡、组织结构变化、和血浆无机离子的变化可以被认为是抗生素毒性研究的可靠生物标志物。这项研究可能是进一步毒性研究的主要平台，以了解环丙沙星对水生生物的潜在分子影响和不利影响。