Effects of fluoride on metamorphosis, thyroid and skeletal development in Bufo gargarizans tadpoles
This study examined the effects of chronic fluoride exposure on metamorphosis, thyroid and skeletal development in tadpoles of Chinese Toad, Bufo gargarizans. The tadpoles were exposed to fluoride concentrations either at 0, 1, 5, 10, or at 50 mg L(-1) from Gosner stage 26 to Gosner stage 42. Body w...
| Veröffentlicht in: | Ecotoxicology (London, England). - 1992. - 22(2013), 7 vom: 27. Sept., Seite 1123-32 |
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| Weitere Verfasser: | , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2013
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| Zugriff auf das übergeordnete Werk: | Ecotoxicology (London, England) |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't RNA, Messenger Thyroid Hormones iodothyronine deiodinase type III EC 1.11.1.- Iodide Peroxidase EC 1.11.1.8 Fluorides Q80VPU408O |
| Zusammenfassung: | This study examined the effects of chronic fluoride exposure on metamorphosis, thyroid and skeletal development in tadpoles of Chinese Toad, Bufo gargarizans. The tadpoles were exposed to fluoride concentrations either at 0, 1, 5, 10, or at 50 mg L(-1) from Gosner stage 26 to Gosner stage 42. Body weight, total length and percentage of tadpoles reaching metamorphosis climax were recorded, and thyroid histological examinations were employed. In addition, mRNA expression of both deiodinase type 2 (D2) and deiodinase type 3 (D3) was analyzed by using RT-PCR and skeletal systems were investigated by using double-staining methodology at stage 42. Results showed that total length and body weight were unaffected by fluoride exposure at all concentrations while metamorphosis was strongly inhibited only by 50 mg L(-1) fluoride. Histomorphological measurements showed the percentage of colloid depletion in thyroid gland increased significantly, while the average diameter of follicles was significantly shorter at 50 mg L(-1) concentration. In addition, fluoride at 5 mg L(-1) can stimulate bone mineralization, while fluoride at 50 mg L(-1) can retard deposition of calcium. In conclusion, our study suggests that 50 mg L(-1) fluoride could damage follicular cells in thyroid gland and induce a sharp reduction in thyroid hormone probably through the up-regulation of D3 mRNA expression, and these influences on thyroid system may delay metamorphosis as well as ossification in bone tissue by inhibiting calcium deposition |
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| Beschreibung: | Date Completed 03.03.2014 Date Revised 13.12.2023 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1573-3017 |
| DOI: | 10.1007/s10646-013-1099-0 |