title: Toxic effects of diclofenac on life history parameters and the expression of detoxification-related genes in Daphnia magna.
abstract: Diclofenac (DCF), as a widely used drug, has been detected in various environmental media such as municipal wastewater effluent. However, there is little information on the effects of DCF on freshwater invertebrates potentially exposing to its residues in surface water. In the present study, we investigated the toxic effects of DCF on the physiological parameters (e.g., survival, growth rate, and reproduction) of a crustacean, Daphnia magna, via a 21-d chronic toxicity test, and we also evaluated the effects of DCF on the expression of the genes related to the detoxification metabolism, growth, development and reproduction (e.g., HR96, P-gp, CYP360A8, CYP314, GST, EcR and Vtg) in acute exposure (up to 96h) with RT-PCR. Significant toxic effects of DCF to D. magna were observed at 50μgL-1, the expression of these selected genes was inhibited with 24h of exposure, and induced after 48h to some extents. The expression of Vtg was induced at high concentrations of DCF (500μgL-1and 5000μgL-1) after 24h and 48h of exposure, but also significantly induced at low concentration (50μgL-1) after 96h of exposure. Dose- and time-dependent relationships were observed for gene expression of the seven selected genes. In the 21-d chronic toxicity test, the days to the first brood and the days to the first egg production were both significantly delayed at 50μgL-1. However, there were no significant differences observed among the molting frequency, number of eggs produced in the first brood, total number of eggs per individual, total number of broods per individual, body length and intrinsic growth rate. Our results suggested that the reproduction parameters are more sensitive endpoints than the survival and growth for evaluating the toxicity of DCF to aquatic invertebrates.
authors.affiliation: Department of Ecology/Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Ecology/Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Ecology/Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
authors.forename: Benben
authors.initials: B
authors.lastname: Pan
authors.affiliation: Department of Ecology/Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Ecology/Institute of Hydrobiology, Jinan University, Guangzhou 510632, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Bao
authors.affiliation: Department of Ecology/Institute of Hydrobiology, Jinan University, Guangzhou 510632, China; Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China. Electronic address: txpnie@jnu.edu.cn.
authors.forename: Xiangping
authors.initials: X
authors.lastname: Nie
mesh_terms: D000818:Animals; D003621:Daphnia / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D004008:Diclofenac / Q000633:toxicity*; D005260:Female; D005618:Fresh Water; D015870:Gene Expression / Q000187:drug effects; D012098:Reproduction / Q000187:drug effects; D036401:Toxicity Tests, Chronic; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D004008:Diclofenac
keywords: Chronic toxicity; Daphnia magna; Detoxification; Diclofenac; Gene expression