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Li J, Dong T, Keerthisinghe TP, Chen H, Li M, Chu W, Yang J, Hu Z, Snyder SA, Dong W, Fang M. Long-term oxytetracycline exposure potentially alters brain thyroid hormone and serotonin homeostasis in zebrafish. JOURNAL OF HAZARDOUS MATERIALS 2020; 399:123061. [PMID: 32485476 DOI: 10.1016/j.jhazmat.2020.123061] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/22/2020] [Accepted: 05/25/2020] [Indexed: 05/06/2023]
Abstract
The impact of oxytetracycline (OTC) exposure in water on the fish still remains unclear. We hypothesized OTC exposure could alter fish gut microbiome and affect thyroid hormone and serotonin homeostasis in the brain via "chemical-gut-brain" axis. Here, ∼2-month-old juvenile zebrafish (Danio rerio) was exposed to two concentrations of OTC (1 and 100 μg/L) for one month until adulthood. Thyroxine-associated gene analysis in the brain revealed that deiodinase 2 (DIO2), deiodinase 3 (DIO3), and thyroid hormone receptor beta (THRβ) expression was significantly decreased. Quantification of thyroid hormones showed a decrease in triiodothyronine (T3) under OTC treatment, which agrees with reduced activity of DIO2. For the serotonin (5-HT) synthesis, the expression of tryptophan hydroxylase (TPH2) was 41 % and 9.3 % of the control group for 1 and 100 μg/L OTC exposed groups; respectively. The intestinal 16S rRNA analysis revealed an increased abundance of Fusobacteria and Proteobacteria, while Actinobacteria was decreased significantly. The altered microbial balance between Proteobacteria and Firmicutes have been previously reported to affect nutrient uptakes such as zinc, which can potentially reduce the activity of DIO2. In summary, this study suggests that long-term OTC exposure not only alters gut microbiome but also changes thyroid hormone and serotonin homeostasis.
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Affiliation(s)
- Jiawei Li
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, 028000 China
| | - Ting Dong
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; School of Environment, Jinan University, Guangzhou, Guangdong, 511443, China
| | - Tharushi P Keerthisinghe
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; Nanyang Environment & Water Research Institute, Nanyang Technological University, 637141, Singapore
| | - Hao Chen
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, 028000 China
| | - Ming Li
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, 028000 China
| | - Wenqing Chu
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, 028000 China
| | - Jingfeng Yang
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, 028000 China
| | - Zongfu Hu
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, 028000 China
| | - Shane Allen Snyder
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; Nanyang Environment & Water Research Institute, Nanyang Technological University, 637141, Singapore
| | - Wu Dong
- Inner Mongolia Key Laboratory of Toxicant Monitoring and Toxicology, College of Animal Science and Technology, Inner Mongolia University for Nationalities, Tongliao, Inner Mongolia, 028000 China.
| | - Mingliang Fang
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore; Nanyang Environment & Water Research Institute, Nanyang Technological University, 637141, Singapore.
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