红霉素对大型溞生殖、生长和基因表达的生态毒理效应

Ecotoxicity of erythromycin on reproduction,growth and genetic expression in Daphina magna

红霉素(ERM)在水环境中广泛检出,并产生生态毒理风险。以大型溞为模式生物,研究了ERM在浮游动物繁殖、生长、抗氧化及神经系统方面的慢性毒理效应。结果表明ERM对大型溞的急性毒性为低毒(48 h-LC_(50)为315.41 mg/L,96 h-LC_(50)为163.08 mg/L)。在2μg/L和200μg/L浓度下暴露21 d,ERM会干扰大型溞的繁殖、生长、氧化应激防御及解毒相关基因的表达,诱导丙二醛含量上升,抑制抗氧化系统超氧化物歧化酶和谷胱甘肽转移酶及神经系统乙酰胆碱酯酶活性,引起细胞膜损伤和神经传导紊乱,造成大型溞前期产卵率升高,且对生长发育和游泳行为产生不利影响。解析了ERM在浮游动物繁殖、生长及在蛋白和基因水平上的毒理响应,为揭示抗生素对水生生物种群稳定和生态系统安全的影响提供基础数据支撑。

Erythromycin(ERM)is a macrolide antibiotic and is widely used to prevent and treat respiratory tract infections,acute pelvic inflammatory disease,amygdalitis,skin infection,and so on.ERM is of high concern due to their abundant occurrence in various environmental media and their toxic risk to aquatic organisms.However,knowledge on the molecular mechanisms of ERM toxicity and its effects on reproduction and growing development output remain scarce.In order to reveal the ecotoxicological effects of ERM on aquatic organisms,acute toxicity and chronic effects of reproduction,growth and development were conducted on the standard model organism Daphnia magna.The results of acute toxicity showed that the LC_(50)of ERM for the 48 h and 96 h were 315.41 mg/L and 163.08 mg/L,respectively,belonging to low toxicity under the rules for classification and labelling of chemicals.In this experiment,0.01‰(2μg/L)and 1‰(200μg/L)of 96 h-LC_(50)were selected as the exposure concentrations for ERM chronic toxicity test.During the chronic toxicity test of 21 days,the ecological behavior indexes related to the growth,development and reproduction of Daphnia magna were recorded,and the population growth indexes were calculated.At the end of the 21-day exposure,the enzyme activities of antioxidant system and neurological system and the expression of genes related to growth,reproduction and metabolism of Daphnia magna were investigated.Following ERM exposure at concentrations of 2μg/L and 200μg/L,phenotypic traits including growing development(body length,heart rate,thoracic limb activity)and fecundity(number of offspring,number of offspring per brood per female,intrinsic rate of increase)were obviously increased,and swimming activity(swimming trajectory and swimming speed)were clearly reduced.Lipid peroxidation malondialdehyde contents were significantly increased at day of 21,the antioxidant enzymes(superoxide dismutase and glutathione S-transferase)and neurotoxic enzymes(acetylcholinesterase)exhibited a trend towards inhibition at higher concentration,suggesting that ERM could result in oxidative damage and nerve conduction disorder.Upregulation of genes involved in reproductive and developmental process,including vg1,vtg2,jhe,ecrb and cyp314 were observed,meanwhile the genes related to lipid metabolism and detoxification(hr96 and P-gp)were clearly inhibited,which regulates the phenotypic traits and corresponding protein levels of Daphnia magna.The alterations in developmental and reproductive system as well as the disturbed antioxidant system and neurological system of zooplankton for ERM provides basic data support for revealing the effects of antibiotics on aquatic organism population stability and ecosystem security.