碩士 / 國立東華大學 / 海洋生物多樣性及演化研究所 / 97 / Polybrominated diphenyl ethers (PBDEs) are an emerging group of endocrine
disruptors. They are widely used as flame-retardants in various commercial products.
PBDEs are structurally stable and have extensive distribution in the environment. They
are lipophilic, bioaccumulative and may be biomagnified through the food chain.
PBDEs may cause negative effects such as dioxin-like toxicity, endocrine disruption, or
interferring sexual differentiation. However, effects of PBDE exposure on gene
expression in fish are not yet well studied. Because PBDE-47 is normally the most
abundant congener found in animal tissues, we orally exposed zebrafish to PBDE-47 (0,
10, 1000 ng/g) from 20 days post hatch （20 dph）to 90 dph. Fish were randomly
sampled at 38 dph and 90 dph for gene expression analysis with QPCR technique. The
rpl8(ribosomal protein L8) gene was used as the endogenous control. The target genes
analyzed for 38 dph samples include sex differentiation related genes （vtg1, amh,
cyp11b2）, dioxin-like toxicity related genes（arnt, ahr2, cyp1a1）, and thyroid-system
related genes（TSH, D1, TTR）. For 90 dph samples, we only focused on the genes
related to dioxin-like toxicitity（arnt1, ahr2, cyp1a1） and thyroid-system （TSH, D1,
TTR）. Our results did not follow a typical dose-response relationship in gene
expressions. On 38 dph, expression of cyp11b2, ahr2 were significantly different between low dose treatment（10 ng/g） and high dose treatment（1000 ng/g）; D1 expression was significantly different in the low dose treatment but not in high dose group when compared to the control. On 90 dph, TSH and ahr2 expressions in high dose treatment were significantly different from control; ahr2 expression in low dose group was also significantly different from high-dose group. Our study demonstrated that PBDE-47 caused transcriptional effects on genes related to sex differentition, thyroid-system and dioxin-like toxicity. Our result suggested that PBDE-47 has weak dioxin-like toxicity compared to TCDD and PCB. PBDE-47 may cause negative effect on gonad development and thyroid system via interfering the expression of cyp11b2, TSH, and D1 genes.
| Identifer | oai:union.ndltd.org:TW/097NDHU5270011 |
| Date | January 2009 |
| Creators | Yu-Chen Hsiao, 蕭玉晨 |
| Contributors | Te-Hao Chen, 陳德豪 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 86 |
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