Endocrine disrupting effects of tebuconazole on different life stages of zebrafish (Danio rerio)

Abstract

Tebuconazole is a widely used fungicide that has been detected in water ecosystems, of which the concentrations may affect the endocrine function of aquatic organisms. At present study, tissue-specific bioaccumulation of tebuconazole was found in ovary of adult zebrafish, indicating a potential risk of endocrine disruption. In order to evaluate the potential endocrine disrupting effects, three life stages (2 hpf (hours post-fertilization) À60 dpf (days post-fertilization), Stage I; 60e120 dpf, Stage II; 180e208 dpf, Stage III) of zebrafish (Danio rerio) were chronically exposed to tebuconazole at the concentrations ranging from 0.05 mg/L to 1.84 mg/L. Result showed that exposed to tebuconazole could lead to a malebiased sex differentiation in juvenile zebrafish and significant decrease of the percentage of germ cells in sexually-mature zebrafish. Egg production was significantly inhibited by 57.8% and 19.2% after Stage IIand Stage III-exposures, respectively. The contents of 17b-estradiol in gonad decreased by 63.5% when exposed to 0.20 mg/L tebuconazole at Stage II and by 49.5% after exposed to 0.18 mg/L tebuconazole at Stage III, respectively. For all stages exposure, reductions in 17b-estradiol/testosterone ratio were observed, indicating an imbalance in steroids synthesis. Additionally, tebuconazole reduced the expression of cyp19a, which was consistent with the decrease of E2 level. In overall, the present findings indicated that, playing as an anti-estrogen-like chemical, tebuconazole inhibited the expression of Cyp19, thereby impairing steroid hormones biosynthesis, leading to a diminished fecundity of zebrafish.

Transgenerational reproductive and developmental toxicity of tebuconazole in Caenorhabditis elegans

“…Abnormal gonadal development, including promotion or retardation of developmental processes, not only causes disease, but also causes inter‐generational effects (Tokumoto et al, ). It was shown that TEB bio‐accumulated significantly more in the gonads than in other tissues (except liver) and gonadosomatic index (GSI) values (gonad weight/body weight × 100) significantly reduced after exposure to TEB in adolescence male and female zebrafish, indicating that TEB disrupted gonadal development (Li et al, ). Consistent with that study, TEB exposure retarded gonadal development in C.elegans , as shown by a dose‐dependent increase in the number of worms that remained in larval stages.…”

Molecular docking and dynamics simulation to screen interactive potency and stability of fungicide tebuconazole with thyroid and sex hormone‐binding globulin: Implications of endocrine and reproductive interruptions

“…The tebuconazole is known to have thyroid disrupting potential (Liang et al, 2015; Li et al, 2019). The TBG binds with thyroid hormones and play important roles in the circulation of thyroid hormones (Chakravarthy & Ejaz, 2020).…”

“…However, 2.1 to 15.5 pg of tebuconazole in 1 mg of hair has been reported during occupational and environmental exposure (Mercadante et al, 2018; USEPA, 2020). The endocrine disruption of tebuconazole was found with the concentrations at 0.05, 0.20, and 0.50 mg/L in zebrafish (Li et al, 2019). In addition, exposure of 0.20 and 0.50 mg/L tebuconazole reduces thyroxine and triiodothyronine in F0 generation of zebrafish (Li et al, 2019).…”

“…However, Liang et al (2015) has reported that hexaconazole and tebuconazole exposure has altered thyroid hormone and gene expression levels in zebrafish larvae. In addition, Liang et al (2015) found that fungicide difenoconazole has potency to change thyroid hormone and gene expression in zebrafish larvae and in different life stages of zebra fish (Li et al, 2019).…”

Enhanced Visible Light Photocatalytic Activity of TiO2 Nanospheres/SnO2 Quantum Dots Composite for Degradation of 4-Nitrophenol

“…Composite of TiO2 and SnO2 QDs may prove to be beneficial for efficient decomposition of Endocrine Disrupting Chemicals (EDCs). Exposure to EDCs in nature is a basic worry with unclear long-term negative impacts [12][13][14][15][16][17][18][19][20][21]. EDCs are discharged into nature by people, animals and industry; and therefore, enters in bodies through soil, surface water and ground water.…”