抗生素药物环丙沙星对锦鲤抗氧化系统的毒性作用

Toxicity effect of ciprofloxacin hydrochloride exposure to the antioxidant systems on Cyprinus carpio

采用暴露试验方法，研究了抗生素药物环丙沙星（Ciprofloxacin，CPFX）的急性毒性和对锦鲤肝脏抗氧化系统中超氧化物歧化酶（SOD）、谷胱甘肽硫转移酶（GST）活性及还原型谷胱甘肽（GSH）、丙二醛（MDA）含量的影响。结果表明：CPFX对锦鲤不产生急性毒性；SOD活性在暴露前中期（3-9 d）受到不同程度的诱导，后期（12-15 d）受到显著抑制（ p 〈0.05）；MDA含量在暴露前中期显著增加（ p 〈0.05）；GSH含量与GST活性变化趋势相似，0.05 mg/L、0.5 mg/L处理组表现出持续性诱导状态，5 mg/L、50 mg/L处理组表现出先上升后下降的变化规律，且在中期（9 d）达到顶峰，GST与GSH在诱导程度上表现出一定的剂量-时间效应关系。研究表明，CPFX暴露对锦鲤造成的氧化损伤是可逆的，机体抗氧化系统并未遭受破坏；GSH和GST响应敏感，适合作为CPFX暴露的生物标记物。

This paper is aimed at determining the potential toxicity effects of ciprofloxacin hydrochloride （CPFX） on the antioxidant system of aquatic organism in the aquatic pollution environment. To achieve the research goal, a 15-day exposure experiment has been laid out and conducted to test the acute toxicity and antioxidant responses of Cyprinus carpio exposed to the aquatic bodies at different concentrations of CPFX. In this exposure test the enzyme activities of the super-oxide dismutase （SOD）, the glutathione-s-transferase （GST）, the contents of glutathione （GSH） and malondialdehyde （MDA） in the liver tissues of Cyprinus carpio were measured. The measurement results showed no acute toxicity of CPFX was found for the tested fish. When the fish was exposed to the different concentrations of CPFX for 15 d, the SOD activities in the liver tissues of Cyprinus carpio in each exposure group were induced by different degrees during one prometaphase stage （3-9 d）, and then significantly inhibited （ p 〈0.05） for the following exposure period （12-15 d）; the MDA content in the exposure group was found higher than in the control group （ p 〈0.05） during the prometaphase stage of exposure test, but no lipid peroxidation was found for the later exposure period. The similar tendency of glutathione-S-transferase （GST） activities and glutathione （GSH） contents was observed in the liver of Cyprinus carpio after 15 d exposure to CPFX. GST activities and GSH contents were induced continuously at lower exposure concentration groups （0.05 mg/L and 0.5 mg/L）. At higher exposure concentration groups （5 mg/L and 50 mg/L）, they all increased at first and reached the highest at 9 d, and then decreased. Besides, an obvious dose-time effect relationship was found in GST and GSH. In summary, the present study demonstrated that oxidative damage of CPFX to Cyprinus carpio was reversible during the 15 d exposure period, and the antioxidant defense systems were undamaged. Of all the different measured parameters, GST and GSH were suitable to be used as potential biomarkers due to their higher sensitivities than the other parameters to the chronic exposure of CPFX at the environmental levels.