Gene expression profiles in brain of male juvenile zebrafish (Danio rerio) treated with triclosan.

Triclosan (TCS) is a broad-spectrum antibacterial agent and has been widely used in a diversity of personal care products. However, recent studies suggest that TCS has some adverse effects, and some evidences suggest in vitro neurotoxicity and developmental neurotoxicity of embryos. There are currently few studies concerning the mechanisms of TCS induced late developmental neurotoxic effect. Therefore, we investigated effects of juvenile zebrafish (Danio rerio) exposure to TCS. Male juvenile zebrafish were exposed to 68.0 µg/L TCS for 42 days. After the exposure experiment, eight Agilent Zebrafish V3 Gene Expression Microarrays were used to identify gene expression changes on brains from the control and TCS treated zebrafish. Microarray analysis yielded 364 differentially expressed genes (FDR adjusted P-value <.05; fold change >2) predominately represented by visual perception, immune system process, multicellular organismal development, antigen processing and presentation, macrophage differentiation functional categories. Pathway analysis showed that TCS mainly influenced Phototransduction and Cytokine-cytokine receptor interaction. In addition, visual perception functional genes involved in Phototransduction were upregulated, while immune system process functional genes involved in Cytokine-cytokine receptor interaction were downregulated. Quantitative real-time PCR (qRT-PCR) analysis confirmed the microarray data. These data suggest that TCS could affect visual centers, immune system, and development in the brain of juvenile fish to cause central neurotoxicity. Our study reveals new molecular targets for TCS and provides further insights into the molecular mechanisms of TCS toxicity during late development.

Effects of volatile organic compounds and carbon monoxide mixtures on learning and memory, oxidative stress, and monoamine neurotransmitters in the brains of mice.

In this study, we investigated the effect of inhaled mixtures of volatile organic compounds (VOCs) and carbon monoxide (CO) on neuroethology. Fifty 6-week-old male Kunming mice were exposed in five similar static chambers; zero (control) and four different doses of VOC and CO mixtures (G1-G4) for 10 consecutive days and 2 h/day. The compounds and concentrations were as follows: formaldehyde, benzene, toluene, xylene, and CO as 0.10 + 0.11 + 0.20 + 0.20 + 10.00 mg/m3, 0.20 + 0.22 + 0.40 + 0.40 + 20.00 mg/m3, 1.00 + 1.10 + 2.00 + 2.00 + 100.00 mg/m3, and 5.00 + 5.50 + 10.00 + 10.00 + 500.00 mg/m3, respectively, which corresponded to 1, 2, 10, and 50 times the indoor air quality standard in China. Morris water maze and grip strength tests were performed during the exposure experiment. One day following the final exposure, oxidative damage levels, monoamine neurotransmitters, monoamine oxidase (MAO), and morphology of mice brain were analyzed. Escape latency, dopamine, norepinephrine (NE), and serotonin decreased significantly, while total antioxidant capacity, glutathione peroxidase, and MAO increased significantly in G3 and G4. In addition, there were morphological changes and degeneration of neurons in the dentate gyrus regions of the hippocampus in G4. Results showed that the inhaled mixtures of VOCs and CO affected learning and memory of mice. The impairment of monoamine neurotransmitter associated with MAO may be one of the mechanisms of learning and memory impairment of the mice induced by the mixtures of VOCs and CO.

Effects of triclosan on hormones and reproductive axis in female Yellow River carp (Cyprinus carpio): Potential mechanisms underlying estrogen effect.

Triclosan (TCS), a member of the class of compounds called pharmaceutical and personal care products (PPCPs), is a broad antibacterial and antifungal agent found in a lot of consumer products. However, TCS hormone effect mechanism in teleost female fish is not clear. Female Yellow River carp (Cyprinus carpio) were exposed to 1/20, 1/10 and 1/5 LC50 TCS (96h LC50 of TCS to carp) under semi-static conditions for 42days. Vitellogenin (Vtg), 17ß-estradiol (E2), testosterone(T), estrogen receptor (Er), gonadotropin (GtH), and gonadotropin-releasing hormone (GnRH) levels were measured by enzyme-linked immunosorbent assay (ELISA). Meanwhile, we also examined the mRNA expressions of aromatase, GtHs-ß, GnRH, and Er by quantitative real-time PCR (qRT-PCR). The results indicated that 1/5 LC50 TCS induced Vtg in hepatopancreas of female carps by interference with the hypothalamic-pituitary-gonadal (HPG) axis at multiple potential loci through three mechanisms: (a) TCS exposure enhanced the mRNA expression of hypothalamus and gonadal aromatase which converts androgens into estrogens, subsequently increasing serum concentrations of E2 to induce Vtg in hepatopancreas; (b) TCS treatment increased GnRH and GtH-ß mRNA expression and secretion, causing the disturbance of reproductive endocrine and the increase of E2 to induce Vtg in hepatopancreas; (c) TCS exposure enhanced synthesis and secretion of Er, then it bound to Er to active Vtg synthesis. These mechanisms showed that TCS may induce Vtg production in female Yellow River carp by Er-mediated and non-Er-mediated pathways.

Effects of immunological and hematological parameter in mice exposed to mixture of volatile organic compounds.

Exposure to some kinds of volatile organic compounds (VOCs) leads to immune system disorders, liver and kidney damage, hematological change. However, there is little information about the effect of VOCs mixture on immune system and hematological parameter. In this study, 50 Kunming male mice were exposed in five similar chambers, 0 (control) and four different doses of VOCs mixture (G1-4) for consecutively 10 days at 2 h/day. The concentrations of VOCs mixture were as follows: formaldehyde, benzene, toluene and xylene 1.0 + 1.1 + 2.0 + 2.0, 3.0 + 3.3 + 6.0 + 6.0, 5.0 + 5.5 + 10.0 + 10.0 and 10.0 + 11.0 + 20.0 + 20.0 mg/m(3), respectively, which corresponded to 10, 30, 50 and 100 times of indoor air quality standard in china. One day following VOCs exposure, spleen T lymphocyte subpopulation, serum biochemical markers and peripheral blood cells in mice were analyzed, respectively. VOCs exposure decreased significantly erythrocyte count (RBC), platelet (PLT) in peripheral blood in mice. While aspartate aminotransaminase (AST), alanine aminotransaminase (ALT), alkaline phosphatase (ALP) and creatinine (CREA) in serum increased significantly in G4 mice versus controls. Flow cytometry analysis showed that the number of splenic lymphocyte subpopulation cells decreased significantly in G2, 3 and 4 mice in comparison with normal Kunming mice. These results indicate inhalation of VOCs mixture affects CD4/8 subpopulations, liver, kidney function and some hematological parameters in mice.

Exposure to triclosan changes the expression of microRNA in male juvenile zebrafish (Danio rerio).

Triclosan (TCS) is a broad-spectrum antibacterial agent which is widely used in various personal care products and cosmetics. It has been found that TCS affects endocrine, immune, nervous, reproductive, and developmental system. Although microRNAs (miRNAs) act a pivotal part in lots of metabolic activities, whether and how they are related to the process of TCS-induced toxicity is unknown. In the present study, TCS induced changes in miRNAs and target gene expression in male zebrafish (Danio rerio) brain, and the potential mechanism was studied. Male juvenile zebrafish were exposed to 0 and 68 µg/L TCS for 42 d. miRNA was isolated from the brain pool of the zebrafish and the expression profiles of 255 known zebrafish miRNAs were analysed by using Affymetrix miRNA 4.0 microarrays. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to assay the expression of 5 differentially expressed miRNAs in the microarray data and some related-genes in brains. The GO term analysis revealed that miRNAs significantly affected by TCS exposure were mainly involved in translation, transcription, DNA-templated, protein transport, and motor neuron axon guidance biological process. Pathway analysis showed that target genes of 5 differentially expressed miRNAs prominently participate in basal transcription factors, purine metabolism, and ribosome biogenesis in eukaryotes. In addition, key genes in purine metabolism pathway and oxidative stress related-genes were significantly changed. These findings offer novel insight into the mechanisms of epigenetic regulation in TCS-induced toxicity in male zebrafish, and distinguish novel miRNA biomarkers for exposure to TCS.

Effects of triclosan (TCS) on hormonal balance and genes of hypothalamus-pituitary- gonad axis of juvenile male Yellow River carp (Cyprinus carpio).

Triclosan (TCS) is a broad spectrum antimicrobial agent which has been widely dispersed and determinated in the aquatic environment. However, the effects of TCS on reproductive endocrine in male fish are poorly understood. In this study, male Yellow River carp (Cyprinus carpio) were exposed to 0, 1/5, 1/10 and 1/20 LC50 (96 h LC50 of TCS to carp) TCS under semi-static conditions for 42 d. Vitellogenin (Vtg), 17ß-estradiol (E2), testosterone(T), gonadotropin (GtH), and gonadotropin-releasing hormone (GnRH) levels were measured by enzyme-linked immunosorbent assay (ELISA). Meanwhile, we also examined the mRNA expressions of aromatase, GtHs-ß, GnRH, estrogen receptor (Er), and androgen receptor (Ar) by quantitative Real-time Polymerase Chain Reaction (qRT-PCR). TCS induced Vtg levels of hepatopancreas, E2 levels of serum, and inhibited Ar and Er mRNA levels, suggesting that the induction of Vtg production by TCS was indirectly caused by non-Er pathways. TCS-induced Vtg levels by interfering with the reproductive axis at plenty of latent loci of male carps: (a) TCS exposure increased the aromatase mRNA expression of hypothalamus and gonad aromatase, consequently increasing serum concentrations of E2 to induce Vtg in hepatopancreas; (b) TCS treatment changed GtH-ß and GnRH mRNA expression and secretion, causing the disturbance of reproductive endocrine; (c) TCS exposure decreased Ar mRNA levels, indicating potential Ar-mediated antiandrogen action. These mechanisms showed that TCS may induce Vtg production in male carp by non-Er-mediated pathways.

Gene expression profiles in promoted-growth rice seedlings that germinated from the seeds implanted by low-energy N+ beam.

The stimulation effect that some beneficial agronomic qualities have exhibited in present-generation plants have also been observed due to ion implantation on plants. However, there is relatively little knowledge regarding the molecular mechanism of the stimulation effects of ion-beam implantation. In order to extend our current knowledge about the functional genes related to this stimulation effect, we have reported a comprehensive microarray analysis of the transcriptome features of the promoted-growth rice seedlings germinating from seeds implanted by a low-energy N(+) beam. The results showed that 351 up-regulated transcripts and 470 down-regulated transcripts, including signaling proteins, kinases, plant hormones, transposable elements, transcription factors, non-coding protein RNA (including miRNA), secondary metabolites, resistance proteins, peroxidase and chromatin modification, are all involved in the stimulating effects of ion-beam implantation. The divergences of the functional catalog between the vacuum and ion implantation suggest that ion implantation is the principle cause of the ion-beam implantation biological effects, and revealed the complex molecular networks required to adapt to ion-beam implantation stress in plants, including enhanced transposition of transposable elements, promoted ABA biosynthesis and changes in chromatin modification. Our data will extend the current understanding of the molecular mechanisms and gene regulation of stimulation effects. Further research on the candidates reported in this study should provide new insights into the molecular mechanisms of biological effects induced by ion-beam implantation.