產前塑化劑與酚類化合物暴露對新生兒臍帶血去氧核醣核酸與發炎相關基因甲基化之影響

Influence of Prenatal Exposure to Phthalates and Phenols on DNA Methylation in Inflammatory Genes

林依樺(Yi-Hua Lin)

指導教授 ： 劉貞佑

國立臺灣大學/公共衛生學院/環境衛生研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.01168

摘要

背景及目的: 孩童健康一直以來都是受重視的議題，本研究針對孩童的健康情形在母親懷孕期間，環境中塑化劑及酚類化合物的暴露與出生後孩童健康變化之關係以表基因體學中DNA甲基化修飾技術討論特定基因的變化。包含有鄰苯二甲酸二(2-乙基己基)酯(DEHP)、鄰苯二甲酸二乙酯 (DEP)、鄰苯二甲酸二丁酯(DBP)及鄰苯二甲酸丁苯甲酯 (BBP)等4 種塑化劑及雙酚A(BPA)、辛基酚(OP)、壬基酚(NP)。過去動物實驗指出子宮內或產後暴露以上數種化合物質會影響到孩童的生長發育。而在環境中低劑量的暴露與此些化合物未知的作用機轉將可能藉由表基因修飾機制改變正常基因運作。研究目的為評估產前暴露塑化劑與酚類物質對出生孩童在發炎相關基因上甲基化程度的改變。
方法: 本研究對象為2004年4月至2005年1月期間參與臺灣出生世代長期追蹤研究的母親與嬰兒配對。使用焦磷酸測序技術，量測臍帶血中干擾素r與誘導型一氧化氮合成酶甲基化變異程度。再與不同時期之血清中總IgE濃度及產前暴露塑化劑與酚類化合物在個案檢體中濃度值，進行簡單線性回歸與多重線性迴歸模式討論。
結果: iNOS、IFN-r平均(標準差)甲基化分別為67.96 (5.33)%、89.06 (4.29) % (範圍: 51.84-91.65、64.57-96.26)。簡單與多重線性迴歸分析顯示IFN-r甲基化程度與母親第三孕期尿液中MEP濃度有顯著負相關(簡單線性回歸:β= -0.023 ，p<0.01; 多重線性迴歸:β= -0.029，p<0.01)。iNOS甲基化平均程度與母親懷孕時血清中總IgE濃度有顯著負相關(β= -412.584，p<0.05)。IFN-r甲基化平均與臍帶血液中總IgE濃度有顯著負相關(β= -6.416，p<0.05)。兩歲孩童血液中總IgE濃度與第三孕期尿液中MEHP濃度有顯著負相關(β= -8.015，p<0.05)。出生臍帶血中總IgE濃度與臍帶血中OP濃度有顯著負相關(β= -1.062，p<0.01)。
結論: 本研究指出，產前暴露塑化劑類物質如MEP及MEHP與酚類化合物如OP可能對胎兒在發育過程中的免疫系統有負面影響。此外，研究也發現iNOS第一位點甲基化程度在不同性別嬰兒尚有顯著的差異在女嬰有稍高的結果。

關鍵字

表基因 ； 產前暴露 ； 塑化劑 ； 酚類化合物 ； 發炎相關基因

並列摘要

Background: Children’s health has been a great concern, and this study investigate epigenetic modifications changes and these impact on specific gene expression in children health outcome through maternal exposures of phthalates (i.e. di(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBzP), diethyl phthalate (DEP) ) and phenols (i.e. bisphenol A (BPA), nonylphenol (NP), and octylphenol (OP) ). Evidence for the animal experiences showed that in utero and early postnatal expose these compounds may lead to a comprehensive child health defects. It was that the possible problem through the low level and unknown mechanism have regulated the epigenetic molecular pathways to change gene expressions. Therefore, we try to evaluate the association between different phthalates metabolites, as well as prenatal phenols exposures, and the epigenetic alteration in Inflammatory Genes.
Methods: This study was based on the Taiwan Birth Panel Study (TBPS), which was enrolled from April 2004 to January 2005. A total of 486 mother-infant paired in this study (the Taiwan Birth Panel Study). Three phenols in cord blood, and four phthalates metabolites in urine. In recently experiments, we found the best PCR condition of the selected genes, including IFN-r, and iNOS, so we used PyroMark Q96 ID to analyze two genes’ epigenetic DNA methylation in subjects’ cord blood samples.The gene-specific DNA methylation patterns were quantified in umbilical cord blood using IFN-r and iNOS by pyrosequencing. IFN-r has been identified as a prerequisite in several models of inflammatory and autoimmune diseases. iNOS expression has been found to respond rapidly to different stimuli, including immunostimulatory cytokines, bacterial products, or infection (Alderton et al. 2001).
Results: Mean (SD) methylation levels of iNOS and IFN-r were 67.96 (5.33)% and 89.06 (4.29) % (range: 51.84-91.65% and 64.57-96.26%), respectively. Simple and multiple linear regression models shown a negative association between IFN-r methylation level and 3rd urine MEP concentration (crude model: β= -0.023, p<0.01 ; adjusted model: β= -0.029, p<0.01). iNOS methylation level and maternal blood IgE concentration had a negative association (adjusted model: β= -412.584, p<0.05). IFN-r methylation level and cord blood IgE concentration had a negative association (adjusted model: β= -6.416, p<0.05). 2 years old blood IgE concentration and 3rd urine MEHP concentration had a negative association (adjusted model: β= -8.015, p<0.05). Cord blood IgE concentration and cord blood OP concentration had a negative association (adjusted model: β= -1.062, p<0.01).
Conclusion: Our result suggest that prenatal exposure to phthalates compounds like MEP, MEHP and OP may adverse effect on inflammatory gene methylation patterns and fetal’s developmental immune system. Otherwise, our study find out different iNOS postion 1 methylation level between male and female babies.

並列關鍵字

Epigenetiv ； Prenatal exposure ； Phthalate ； Phenols ； Inflammatory genes

參考文獻

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