氧氟沙星对锦鲤抗氧化系统和DNA损伤的影响

Effects of Ofloxacin on Antioxidant System and DNA Damage of Cyprinus carpio

由于抗生素对人体健康和生态环境潜在的威胁,其大量使用已引起人们广泛关注。该研究通过毒性暴露试验,研究了氟喹诺酮类抗生素氧氟沙星(OFLX)对锦鲤抗氧化酶活性和DNA损伤的影响。结果表明,随着暴露浓度和时间的增加,OFLX对锦鲤鱼肝SOD活性、MDA和GST含量呈现显著的诱导效应。当OFLX浓度200 mg/L,暴露13 d时,锦鲤肝脏各项抗氧化酶活性指标均出现显著降低,表明OFLX对锦鲤的抗氧化系统的累积毒性超出了鱼体的自身调节能力,导致鱼体的抗氧化系统的损伤。鱼鳃组蛋白H2AX(γ-H2AX)磷酸化结果表明,OFLX可造成鱼体DNA损伤,诱导鱼鳃γ-H2AX产生和簇集,且呈现明显的剂量-效应关系。OFLX浓度200 mg/L,暴露4 d时鱼鳃γ-H2AX浓度达到最大值(110.49 ng/L)。随着暴露时间继续增加,各浓度组γ-H2AX含量均有所下降,表明OFLX可能导致造成DNA双链的断裂,导致γ-H2AX浓度下降。该结果为评估OFLX对锦鲤的抗氧化系统和DNA毒性影响提供了较为可靠的依据。

The widely use of antibiotics has gained serious concerns for their potential threat to human health and ecosystem.Ofloxacin（OFLX） is a commonly-used fluoroquinolones antibiotic. In the present study,the antioxidant enzyme activities and DNA damage of OFLX to Cyprinus carpio were investigated by exposure tests. With the increasing exposure concentration and time,a significant inductive effect of OFLX to superoxide dismutase（SOD） activity,malonaldehyde（MDA） and glutathione S-transferase（GST） contents was observed in liver of Cyprinus carpio. These indexes were significantly decreased after exposure to OFLX solution of 200 mg/L at 13 d,demonstrating the insufficiency of self-regulation for eliminating the cumulative toxicity of OFLX in fish body. The intensity change of histone H2 AX phosphorylation in gill of Cyprinus carpio illustrated the generation and clustering of γ-H2 AX,resulting from the DNA damage of these organs after exposure to OFLX. Meanwhile,an obvious dose-response relationship between the exposure concentration/time and the intensity of γ-H2 AX was found. The maximum of γ-H2AX（110.49 ng/L） achieved after 200mg/L exposure for 4 d. Then,γ-H2 AX decrease with the increase of time in each group accounted for the weakening of detoxification that could be attributed to the DNA double-strand break in the gill of Cyprinus carpio. The results would provide a valuable basis for the toxicity evaluation of OFLX to the antioxidant system and DNA damage of Cyprinus carpio.