Project description:Background: Diclofenac is a non-steroidal anti-inflammatory drug frequently found in the aquatic environment. Previous studies have reported histological changes in the liver, kidney and gills of fish at concentrations similar to those measured in treated sewage effluents (~1 µg/L). Analyses or predictions of blood plasma levels in fish allow a direct comparison with human therapeutic plasma levels, and may therefore be used to indicate a risk for pharmacological effects in fish. To relate internal exposure to a pharmacological interaction we therefore investigated global hepatic gene expression together with bioconcentration to blood plasma and liver of rainbow trout (Oncorhynchus mykiss) exposed to waterborne diclofenac. Results: At the highest exposure (81.5µg/L) the fish plasma concentration reached ~88% of the human therapeutic levels (Cmax) after two weeks. Using an oligonucleotide microarray followed by quantitative PCR we found extensive effects on hepatic gene expression at this concentration, and some genes were regulated down to the lowest concentration tested (1.6 µg/L) corresponding to ~1.5% of the human Cmax. Functional analysis of differentially expressed genes revealed effects on biological processes such as inflammation and immune response, in agreement with the expected mode of action of diclofenac. In contrast to some previously reported results, the bioconcentration factor was found to be stable (4.02±0.75 for blood plasma and 2.54±0.36 for liver) regardless of the water concentration. Conclusions: Hepatic gene expression is affected in fish at blood levels similar to and below the human Cmax. This adds confidence to the use of fish blood plasma levels to predict risks for pharmacological responses in fish. The microarray results indicate similarities in the mode of action of diclofenac between humans and fish. The identified set of regulated genes may contain useful exposure biomarkers to be used in complex exposure scenarios. Juvenile rainbow trout was exposed to waterborne diclofenac at a series of different concentrations for 14 days. A flow-through system was used for eight aquaria (two per concentration), each containing 12 trouts. Nominal exposure concentrations: 1µg/L, 10 µg/L, 100 µg/L and control. Total RNA for biotinylated aRNA synthesis was extracted from the liver. Samples of aRNA from two fish from the same aquarium were pooled before the assay. In total, four biochips were analyzed corresponding to 32 microarrays. As we used two aquaria per concentration, these 32 microarrays allowed the analyses of four aRNA pools (eight fish) per aquarium, which is equal to eight pools per concentration of diclofenac.

Project description:Background: Diclofenac is a non-steroidal anti-inflammatory drug frequently found in the aquatic environment. Previous studies have reported histological changes in the liver, kidney and gills of fish at concentrations similar to those measured in treated sewage effluents (~1 µg/L). Analyses or predictions of blood plasma levels in fish allow a direct comparison with human therapeutic plasma levels, and may therefore be used to indicate a risk for pharmacological effects in fish. To relate internal exposure to a pharmacological interaction we therefore investigated global hepatic gene expression together with bioconcentration to blood plasma and liver of rainbow trout (Oncorhynchus mykiss) exposed to waterborne diclofenac. Results: At the highest exposure (81.5µg/L) the fish plasma concentration reached ~88% of the human therapeutic levels (Cmax) after two weeks. Using an oligonucleotide microarray followed by quantitative PCR we found extensive effects on hepatic gene expression at this concentration, and some genes were regulated down to the lowest concentration tested (1.6 µg/L) corresponding to ~1.5% of the human Cmax. Functional analysis of differentially expressed genes revealed effects on biological processes such as inflammation and immune response, in agreement with the expected mode of action of diclofenac. In contrast to some previously reported results, the bioconcentration factor was found to be stable (4.02±0.75 for blood plasma and 2.54±0.36 for liver) regardless of the water concentration. Conclusions: Hepatic gene expression is affected in fish at blood levels similar to and below the human Cmax. This adds confidence to the use of fish blood plasma levels to predict risks for pharmacological responses in fish. The microarray results indicate similarities in the mode of action of diclofenac between humans and fish. The identified set of regulated genes may contain useful exposure biomarkers to be used in complex exposure scenarios.

Project description:Ketoprofen and diclofenac are non-steroidal anti-inflammatory drugs (NSAIDs) often used for similar indications, and both are frequently found in surface waters. Diclofenac affects organ histology and gene expression in fish at around 1 M-BM-5g/L. Here, we exposed rainbow trout to ketoprofen (1, 10 and 100 M-BM-5g/L) to investigate if this alternative causes less risk for pharmacological responses in fish. The bioconcentration factor from water to fish blood plasma was <0.05 (4 for diclofenac based on previous studies). Ketoprofen only reached up to 0.6M-bM-^@M-0 of the human therapeutic plasma concentration, thus the probability of target-related effects was estimated to be fairly low. Accordingly, a comprehensive analysis of hepatic gene expression revealed no consistent responses. In some contrast, trout exposed to undiluted, treated sewage effluents bioconcentrated ketoprofen and other NSAIDs much more efficiently, according to a meta-analysis of recent studies. Neither of the setups is however an ideal representation of the field situation. If a controlled exposure system with a single chemical in pure water is a reasonable representation of the environment, then the use of ketoprofen is likely to pose a lower risk for wild fish than diclofenac, but if bioconcentration factors from effluent-exposed fish are applied, the risks may be more similar. Ketoprofen (purity M-bM-^IM-%98%) (Sigma-Aldrich, Steinheim, Germany) was dissolved in water (500 mg/L concentrated solution), stirred vigorously and diluted stepwise to obtain stock concentrations (0.5 mg/L, 5 mg/L and 50 mg/L). Juvenile rainbow trout (Oncorhynchus mykiss) of both sexes (age: approximately six months, weight: 39.4M-BM-16.6g) were obtained from VM-CM-$nneM-CM-%ns fiskodling AB, Sweden, and kept in 500 L holding tanks with sand-filtered, aerated fresh water in a flow-through system for one week prior to the experiment. Eight experimental 48 L glass aquaria, semi-covered in black plastic bags to reduce visual stress from the outside (12:12 h light:dark photocycle), were supplied with filtered, aerated freshwater at a flow rate of 0.25 L/min. At the onset of the experiment 80 trout were randomly divided among the aquaria (ten fish in each). Peristaltic pumps (500 M-BM-5l/min) from each stock solution were used to reach target ketoprofen concentrations of 0 (control), 1 (low), 10 (intermediate) and 100 (high) M-BM-5g/L with two aquaria for each concentration. Water samples were taken from each aquarium at day 1, 7 and 14 and stored at -20M-BM-0C until analysis. To minimize biological variation due to variable food intake, the fish were not fed during the exposure period. It should be stressed that trout readily cope with food deprivation for much longer periods at these temperatures [Kullgren et al., 2010]. To ensure a stable water quality, temperature (12.9M-BM-10.1M-BM-0C), pH (7.4M-BM-10.2) and oxygen saturation (88.3%M-BM-11.3) were monitored every third day. The total organic carbon content of the supply water was 2.5 mg/L. At the experiment termination on day 14, the fish were killed by a rapid blow to the head and blood was collected from the caudal vessels by the use of heparinized syringes. The plasma was instantly separated by centrifugation at 10,000 rpm for 2 min and snap frozen in liquid nitrogen. The length and weight of the fish were measured and their sex determined by macroscopical observation of their gonads. Liver samples for gene expression analyses were collected and snap frozen in liquid nitrogen. Both liver and plasma samples were stored at M-bM-^HM-^R70M-BM-0C until analysis. All animal experiments were approved by the local animal committee in Gothenburg (permission number 216-2010). A 15k rainbow trout gene expression microarray was designed for the RT analyzer platform (febit, Heidelberg, Germany) using The Institute for Genomic Research (TIGR) Rainbow Trout Gene Index (RTGI) database version 7.0 (http://compbio.dfci.harvard.edu/tgi/). Details on the probe design strategy, but for eelpout (Zoarces viviparus), and transcript selection strategy are described elsewhere [Cuklev et al., 2011, Kristiansson et al., 2009, Cuklev et al., 2012]. When available, transcripts at GenBank (http://www.ncbi.nlm.nih.gov/nucleotide) were used. Results from similar microarrays, performed by our research group using the same platform, have shown good correlation with qPCR data [Cuklev et al., Kristiansson et al., 2009, Cuklev et al., 2012, Gunnarsson et al., 2009, Lennquist et al., 2011]. The frozen liver tissue was homogenized using Tissuelyser (Qiagen) and total hepatic RNA was isolated using QIAcube and RNeasyM-BM-. Plus Mini Kit (Qiagen). The RNA quantity was determined with spectophotometric measurements (Nanodrop 1000, NanoDrop Technologies) and the quality was assessed by Experion automated electrophoresis using RNA StdSense chip (Bio-Rad, Sundbyberg, Sweden). Biotinylated aRNA was synthesized using MessageAmpM-bM-^DM-" II-Biotin Enhanced Single Round aRNA Amplification Kit (AmbionM-BM-.). The aRNA samples (20 M-BM-5g) were vacuum dried in a vacuum centrifuge, dissolved in 10 M-BM-5l water and fragmented according to the manufacturerM-bM-^@M-^Ys protocol. The following steps described in this subchapter were all performed by febit. Oligonucleotide arrays were synthesized by photo-controlled in situ synthesis using the Geniom One system (febit). Each biochip consists of eight individually accessible micro-channels, each of which is referred to as a microarray in this manuscript. Four individuals (of both sexes) from each control aquarium and each high exposure concentration aquarium were included in the analysis, i.e. eight fish per exposure concentration. In total, two biochips were analyzed corresponding to 16 microarrays. Pre-hybridization and hybridization were performed based on a customized protocol, described in detail by Cuklev et al. [2011]. The samples were randomly allocated on the biochips. Signals were detected using the internal CCD-camera system of the RT analyzer instrument (febit) and quantified using the Geniom Wizard software. Integration times were 266 and 273 ms, determined automatically by the instrument software. All statistical calculations were done in R-2.12.2 (www.r-project.org) [R Development Core Team, 2010]. The quality of pre- and post-normalized arrays was verified with Box and MA plots. The data analysis was performed in the R-package LIMMA [Smyth, 2004]. Data were normalized using the M-bM-^@M-^XquantileM-bM-^@M-^Y method. Moderated t-statistics and adjusted p-values of differential expression were calculated using the empirical Bayes model. As we found no clear differences between the two control aquaria or between the two aquaria with the highest concentration of ketoprofen (100 M-BM-5g/L), all fish from the same treatment were treated as a single group, i.e. we compared one control group to one group of fish exposed to 100 M-BM-5g/L of ketoprofen.

Project description:These studies aimed to investigate the hepatic transcriptional response of brown trout to the natural estrogen, E2, and the herbicide linuron. We exposed mature male brown trout to three concentrations of each chemical for 4 days and sequenced the hepatic transcriptome of 3 individuals per treatment group in order to determine the global mechanisms of toxicity of these environmental contaminants. We assembled the brown trout transcriptome using a de novo approach. Subsequent differential expression analysis identified a total of 2113 differentially-regulated transcripts in the group exposed to the highest E2 treatment concentration, and 822 differentially-regulated transcripts across all linuron treatments. For E2, differentially-expressed transcripts included those encoding known oestrogen-responsive genes, while regulated processes included those associated with vitellogenesis including lipid metabolism, cellular proliferation and ribosome biogenesis. For linuron, there was a striking down-regulation of transcripts encoding the majority of the enzymes involved in the cholesterol biosynthesis pathway, and also a considerable induction of transcripts involved in cellular stress response including Cyp1a. Fish were exposed to 3 concentrations of E2 (measured concentrations were 1.9, 18.1 and 34.4 ng/L), 3 concentrations of linuron (measured concentrations were 1.7, 15.3 and 225.9 µg/L) and water controls for 4 days. Liver mRNA from 3 replicate individuals per treatment was sequenced in an Illumina HiSeq 2500 platform. Two control groups (n=6 fish in total) were included. Using a de novo approach, we assembled the hepatic transcriptome for brown trout. Sequence reads were re-mapped to the assembled transcriptome using Bowtie2 and transcript expression profiling was conducted using EdgeR. ERCC spike controls were added to all individual samples, allowing for the assessment of the reproducibility and dynamic range for transcript expression quantification in our experiments.

Project description:Atrazine (ATZ) and nonylphenol (NP) are commonly identified contaminants in aquatic habitats; however, relatively few studies have considered the impact of these endocrine disrupters on immune function. This study examined the immunotoxicological effects of ATZ and NP at multiple levels of biological organization. Juvenile rainbow trout (Oncorhynchus mykiss) were exposed to a solvent control (0.00625 % v/v anhydrous ethanol), 59 µg/L ATZ, 555 µg/L ATZ, 2.3 µg/L NP or 18 µg/L NP (measured concentrations) for 4 d. At the end of exposure, fish were assessed for general health indicators (liver somatic index (LSI), spleen somatic index (SSI), hematocrit), biochemical endpoints (plasma cortisol concentrations, lysozyme activity, and protein content), a cellular endpoint (blood leukocyte differential counts), and an integrated immune response at the organism level (host resistance challenge with Listonella anguillarum). Additionally, liver gene expression was assessed using a salmonid microarray (cGRASP, 32K version 1) for fish exposed to the (solvent) control, high ATZ (555 µg/L) and high NP (18 µg/L) treatments. Fish exposed to the high ATZ concentration exhibited elevated plasma cortisol, a decrease in SSI, and decreased lymphocytes and increased monocytes in peripheral blood, with suppression of early immune system processes apparent at the molecular level. In contrast, fish exposed to the high NP concentration showed physiological (e.g. elevated LSI) and gene expression changes (e.g. induction of vitellogenin) consistent with estrogenic effects, as well as decreased lymphocytes in the peripheral blood and more limited alteration in immune system related pathways in the liver transcriptome. Fish exposed to high ATZ or NP concentrations suffered higher mortality than the control group following disease challenge with L. anguillarum. Microarray analysis of the liver transcriptome revealed a total of 211 unique, annotated differentially-regulated genes (DRGs) following high ATZ exposure and 294 DRGs following high NP exposure, with signatures that included alterations to a number of immune-system related processes and pathways. Functional (enrichment) analysis revealed effects on immune system function, metabolism, oxygen homeostasis, cell cycle, DNA damage, and other processes affected by ATZ or NP exposure. Overall this study provides evidence at multiple levels of biological organization that both ATZ and NP are immunotoxic and highlights the potential risk posed by these chemicals to wild fish populations.

Project description:Marker-assisted selective breeding of fish with higher levels of resistance towards specific pathogens has shown successful, but. However, the impact of host genotype on multiple pathogen infections are is still poorly investigated. This study examined the resistance in rainbow trout (Oncorhynchus mykis) towards infection with the eye fluke Diplostomum pseudospathaceum. We used genetically selected rainbow trout, carrying SNPs associated with resistance towards the parasitic ciliate Ichthyophthirius multifiliis, and exposed the fish to eye fluke cercariae. We showed that fish partly resistant to I. multifiliis were more susceptible to eye fluke invasion. Expression The expression of immune relevant genes (encoding innate and adaptive factors) was also affected as these genotypes responded less strongly to a secondary fluke infection. The complexity of genome architecture in disease resistance towards multiple pathogens is discussed. A total of 200 rainbow trout (body weight 14.3-17.7 g, body length 10.2-11.5 cm) were used for the study. Two groups of rainbow trout with high (QTL fish) and low (non-QTL fish) frequency of SNPs associated with I. multifiliis resistance, were hatched from eyed eggs at the disease free recirculated Bornholm Salmon Hatchery, Nexø, Denmark and subsequently reared to the fingerling stage. For this purpose, the first group (QTL-fish) was produced by using sperm from three male genotyped parents carrying SNPs AX-89947214 (Omy17) and AX-89960822 (Omy16), and the other group (non-QTL fish) was produced by using sperm from three other male parents negative for these SNPs. In both cases, sperm was used to fertilize a common pool of eggs stripped from a total of 30 outbred females. Processes of hatching and subsequent rearing of fry to the fingerling stage did not differ between groups of QTL fish and non-QTL fish. From each group (QTL and non-QTL fish) we randomly gathered 100 rainbow trout and transported them (3 h duration) from the hatchery to the infection facility at the University of Copenhagen. Fish were then accommodated and acclimatized 14 d in identical aerated glass tanks with internal biofilters (25 fish per 60 L water, total tank volume 80 L), which were placed in a temperature temperature-controlled room (water temperature constant at 12°C, pH 7.6). We used 30% water change per day to maintain ammonia levels below 0.25. Fish were fed by pelleted feed (1% of fish biomass per day). All fish were genotyped with respect to the two relevant QTLs, one on chomosome 16 and one on chromosome 17. Fish being double heterozugous were excluded from qPCR analysis.

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Does ketoprofen or diclofenac pose the lowest risk to fish?

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