- 學位論文
細胞色素P4502E1與麩胱甘硫轉移酵素基因多型性及活性表現對二甲基甲醯胺職業暴露勞工生物偵測之影響
Effects of Genotyping and Phenotyping of Cytochrome P4502E1 and Glutathione-S-transferase on the Biological Monitoring of Workers with Occupational Exposure to N,N-dimethylformamide
摘要
二甲基甲醯胺 （N,N-dimethylformamide, 簡稱DMF）的代謝酵素細胞色素cytochrome P450 2E1 （簡稱CYP2E1）及麩胱甘硫轉移酵素 （glutathione- S-transferase, GST），在人體內有不同的基因多型性 （genetic polymorphism） ，而表現出的酵素活性 （expression） 亦會影響DMF在體內的代謝情形及所造成的健康效應。本研究目的為：（1）探討代謝酵素CYP2E1與GST之不同基因型及活性表現對DMF職業暴露勞工，其尿中生物暴露指標單甲基甲醯胺 （N-methylformamide, NMF）、DMF、N-acetyl-S-（N-methylcarbamoyl）cysteine （AMCC）的影響，（2）比較DMF暴露及非暴露勞工肝功能異常情形與外在暴露、內在劑量、代謝酵素的基因型及酵素活性的相關性。本研究選取106位勞工（DMF暴露和非暴露者分別為49和57位）為研究對象，針對DMF暴露勞工進行個人空氣、尿液及血液樣本採樣，對非DMF暴露勞工收集其尿液及血液樣本。勞工DMF空氣暴露濃度以被動式採樣器（3M 3500）採集，暴露勞工尿液收集於工作期間與工作後24小時內進行。空氣暴露測定樣本以氣相層析儀 （HP-5890）火焰離子偵檢器（FID）分析，尿液樣本中DMF及NMF濃度以氣相層析儀 （Varian 3600）氮磷偵檢器（NPD）分析，尿液樣本中AMCC濃度以液相層析儀 （HITACHI L-7420）分析。聚合酵素連鎖反應 （polymerase chain reaction, PCR）及電泳層析用以判定基因型，代謝酵素的活性表現以即時聚合脢連鎖反應（Real-time PCR）進行分析。本研究發現：暴露組勞工空氣DMF暴露濃度（ppm）及尿中DMF、NMF及AMCC濃度（mg/L）平均值為7.59、0.76、9.36及15.29。CYP2E1的基因型和三種DMF尿中指標物皆未呈現顯著相關，而尿中AMCC濃度除受到空氣中DMF暴露值影響外，尚受到受測者體內GSTT1及GSTM1的基因型分布的影響。建議以尿中AMCC作為DMF職業暴露的內在指標時，應考量GST的基因多型性，才不致對DMF暴露產生錯估。
並列摘要
The merabolism of N,N-dimethylformamide （DMF） in a human body involves cytochrome P450 2E1 （CYP2E1） and glutathione-S-transferase （GST）. It has been known that these two enzymes own different kinds of genetic polymorphisms. The different genetic polymorphisms of the enzymes make the expressions of the enzyme activities for the metabolism of DMF and the health effects cause by DMF in humans become very different. The objectives of this study are: （1） to investigate the effects of genetic polymorphisms of CYP2E1 and GST on three urinary biomarkers, i.e., N-methylformamide （NMF）, DMF and N-acetyl-S-（N-methylcarbamoyl）cysteine （AMCC）, of DMF exposure; （2） to compare the difference of liver function between workers with and without DMF exposure and to explore the association between genetic polymorphisms and activity expressions of the DMF metabolic enzymes. One hundred and six workers （including 49 workers with DMF exposure and 57 workers without DMF exposure） were recruited in this study. For the workers with DMF exposure, personal full-shift airborne exposure, urine and blood samples were collected. For the workers without DMF exposure, urine and blood samples were collected. Passive samples （3M 3500） were used to measure the personal DMF airborne exposure. The collection of urine samples for the DMF exposed workers was conducted during work shift and in 24 hours after the end of the work shift. The samples of airborne exposure were analyzed by GC/FID （HP-5890）. The amounts of DMF and NMF in the urine samples were measured by GC/NPD （Varian 3600）. The amount of AMCC in the urine samples were measured by HPLC （HITACHI L-7420）. The genetic polymorphisms of CYP2E1 （Pst1 and Dra1）, and GST （T1 and M1） were determined by polymerase chain reaction （PCR） and restriction fragment length polymorphism （RFLP） from the peripheral lymphocytes. We found the average concentrations of DMF in air, DMF, NMF, and AMCC in urine were 7.59 ppm, 0.76, 9.36, and 15.29 mg/L, respectively. No any biomarkers in urine present associations with the CYP2E1 variants. Urinary AMCC, however, revealed a significant association with the variants of both GSTT1 and GSTM1 given adjusted by DMF concentrations in air. We suggested using urinary AMCC as a biomarker of DMF exposure should take into account of GST variants to avoid the erroneous exposure estimate.