Showing papers by "Bingsheng Zhou published in 2022"

Niclosamide Exposure at Environmentally Relevant Concentrations Efficaciously Inhibited the Growth and Disturbed the Liver-Gut Axis of Adult Male Zebrafish.

Abstract: In the current study, adult male zebrafish fed a normal diet (ND) or high-fat diet (HFD) were exposed to niclosamide (NIC) at environmentally relevant concentrations to reveal the accumulation and distribution in different tissues and evaluate the effects on liver-gut axis. Chemical analysis indicated that the liver bore a greater burden of NIC compared with the brain and gonads in adult zebrafish, and the HFD-fed fish bore greater burden in their liver and brain than those ND-fed fish. The indications from body weight, growth rate, body mass index, micro-CT images, biochemical and pathological changes confirmed that NIC can efficaciously curb weight gain and improve overloads of in plasma insulin and glucose in HFD-fed zebrafish. However, the potential effects on liver-gut axis in ND-fed zebrafish were also elucidated: NIC disturbed mitochondrial energy production, inhibited the glycemic and triacylglycerol biosynthesis but promoted triacylglycerol and free fatty acid catabolism, therefore reduced lipid accumulation in hepatocytes; NIC also impaired the physical barrier, evoked inflammatory and oxidative stress and led to microbiota dysbiosis in the intestine. There findings highlighted the necessity for evaluating its potential impacts on the health of wild animals as well as human beings upon long-term exposure.

Nano-TiO2 Adsorbed Decabromodiphenyl Ethane and Changed Its Bioavailability, Biotransformation and Biotoxicity in Zebrafish Embryos/Larvae

Abstract: Decabromodiphenyl ethane (DBDPE), a novel brominated flame retardant, may co-exist with other pollutants including nanoparticles (NPs) in aquatic environment. Due to structural similarity with decabromodiphenyl ether, DBDPE has been reported to exhibit thyroid disrupting effects and neurotoxicity. This study further evaluated the behavior of DBDPE in aqueous environments along with the bioavailability and toxicity of DBDPE in aquatic organisms in the presence of TiO2 nanoparticles (n-TiO2). When co-existing in an aqueous environment, DBDPE was adsorbed by n-TiO2, potentially facilitating the sedimentation of DBDPE from the aqueous phase. Co-exposure to DBDPE and n-TiO2 significantly increased the uptake of DBDPE by zebrafish (Danio rerio) embryos and altered the composition of metabolites in zebrafish larvae compared to zebrafish exposed to DBDPE alone. The DBDPE-induced increases in heart rate, tail bending frequency, average speed under dark/light stimulation, and thyroid hormone levels in zebrafish embryos/larvae were further enhanced in the presence of n-TiO2. Overall, the results demonstrate that n-TiO2 affected the behavior of DBDPE in the aqueous phase and increased the bioavailability and biotoxicity of DBDPE in zebrafish embryos/larvae. These results could be helpful for understanding the environmental behavior and toxicity of DBDPE.

Endocrine disrupting effects induced by levonorgestrel linked to altered DNA methylation in rare minnow (Gobiocypris rarus).

Abstract: Progestins are worldwide environmental contaminants, however, their ecotoxicological risks and underlying molecular mechanisms of effects are not fully understood. In this study, newly hatched rare minnow (Gobiocypris rarus) larvae were exposed to environmentally realistic concentrations (1 and 10 ng/L) of levonorgestrel (LNG) for 6 months. The sex ratios were not affected by LNG at both concentrations, but the growth was significantly inhibited at 10 ng/L while promoted at 1 ng/L. Histological analysis revealed impaired gonadal development. Plasma concentrations of estradiol in females and testosterone in both sexes were significantly induced after exposure to 1 ng/L LNG; plasma concentrations of 11-ketotestosterone were markedly increased in females exposed to 10 ng/L LNG and in males exposed to both concentrations of LNG. The transcription of cyp19a1a was significantly up-regulated in ovaries exposed to LNG at both concentrations, while cyp17a1 was down-regulated in testes exposed to 10 ng/L LNG. The global DNA methylation level was significantly decreased in testes exposed to 10 ng/L LNG, which might be associated with inhibited spermatogenesis. Gender-specific changes in CpG methylation patterns were induced by LNG in the 5' flanking region of cyp19a1a, with hypomethylation in ovaries but hypermethylation in testes, which was linked to the regulation of cyp19a1a transcription. The results suggest that LNG could induce endocrine disrupting effects in fish at environmentally realistic concentrations, which may be linked to altered DNA methylation. This study indicates potentially high ecological risk of LNG to fish populations, and warrants researches on regulatory mechanisms of epigenetic modifications in progestin-induced effects.