三泰芬及邁克尼干擾青鱂魚肝中細胞色素P450活性及全反式視黃酸相關基因表現量之研究

Triadimefon and Myclubutanil Interfere the Activity of Cytochrome P450s and mRNA Expression of All-trans Retinoic Acid-Related Genes in the Liver of Medaka (Oryzias latipes)

林均鴻(Chun-Hung Lin)

指導教授 ： 陳佩貞

國立臺灣大學/生物資源暨農學院/農業化學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.01743

摘要

三泰芬 (Triadimefon) 及邁克尼 (Myclobutanil) 為農業上廣為使用的康唑類殺真菌劑 (Conazoles)。研究顯示三泰芬 (具致腫瘤性) 及邁克尼 (不具致腫瘤性) 會干擾小鼠肝中重要代謝酵素細胞色素P450 (Cytochrome P450, CYP) 基因表現及酵素活性，進而加劇維生素A活性形式全反式視黃酸 (All-trans retinoic acid, atRA) 之代謝。但三泰芬及邁克尼對水生生物之影響的相關研究仍有限，因此本研究探討三泰芬及邁克尼對青鱂魚 (Oryzias latipes, medaka) 肝中CYPs基因表現量、酵素活性及atRA相關基因表現之干擾作用。結果顯示，暴露三泰芬及邁克尼 (2 mg/L) 3天後青鱂魚肝中CYP3A38及CYP3A40之mRNA表現有提升趨勢。暴露三泰芬溶液 (2.0-3.5 μM) 7天後會提升CYP1A和CYP3A活性，而暴露邁克尼溶液 (2.0-3.5 μM) 則僅提升CYP3A活性。此外，合成atRA之酵素ALDH1A2之mRNA表現量不受實驗處理影響，而代謝內生atRA之酵素CYP26B1之mRNA表現量則受三泰芬 (2.0-3.5 μM) 誘導提升，顯示三泰芬造成水生生物中atRA過量代謝的可能性較邁克尼高。在atRA相關受體中，RARγ1受三泰芬 (2.0 μM) 誘導，顯示三泰芬可能經由RARγ1途徑誘導CYP26B1基因表現；而三泰芬及邁克尼 (2.0 μM) 暴露後RXRα1及RXRβ1之mRNA表現量皆下降，顯示三泰芬及邁克尼皆可能會影響細胞對atRA之感知能力，進而影響atRA參與調控之生理機制，但無法以此做為康唑類殺真菌劑是否具有致癌性之生物指標。綜合以上結果，暴露於三泰芬和邁克尼會提高青鱂魚肝臟中特定CYPs基因表現及活性，並干擾atRA相關核受體之mRNA表現，可能會進而影響維生素A之正常代謝及其參與之生理調控機制。

關鍵字

三泰芬 ； 邁克尼 ； 細胞色素P450 ； 全反式視黃酸 ； 青鱂魚

並列摘要

Triadimefon and myclobutanil are triazole-containing conazole fungicides widely used in agriculture. Previous studies show that some conazoles (e.g. triadimefon) at sublethal dose induced gene expression and enzymatic activity of cytochrome P450s (CYPs) in the liver of mouse, leading to a decrease in hepatic level of all-trans retinoic acid (atRA), an active form of vitamin A with anticancer properties. This study demonstrates the effects of carcinogenic triadimefon and non-carcinogenic myclobutanil on the activity of CYPs and mRNA expression of atRA-related genes in the liver of an aquatic organism, medaka (Oryzias latipes). Enzymatic activity analyses show triadimefon (2.0-3.5 μM) induced the activities of CYP1A and CYP3A, while myclobutanil (2.0-3.5 μM) only induced the activity of CYP3A. Quantitative real-time PCR analyses revealed that only triadimefon (2.0-5.0 μM) induced mRNA expression of endogenous atRA metabolism enzyme CYP26B1. Results from both enzymatic and genetic analyses above indicating that triadimefon may enhance hepatic atRA metabolism more severely than myclubutanil could do. Gene expression of atRA-related nuclear receptors retinoid X receptors (rxrα1 and rxrβ1) was depressed by both triadimefon and myclobutanil, indicating that both conazoles may interrupt the ability of cell to sense atRA and leading to disruption of atRA-regulated mechanisms. Overall, both triadimefon and myclobutanil interfere with the activity of cytochrome P450s and mRNA expression of all-trans retinoic acid-related genes in the liver of medaka.

並列關鍵字

Triadimefon ； Myclobutanil ； Cytochrome P450 ； All-trans-retinoic acid ； medaka (Oryzias latipes)

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