Expression of CYP1A1 mRNA in milk cells serves as a biomarker for dioxins exposure?

在知情同意的情况下，于产后一周内在U妇产科诊所采集50名妇女的乳汁和血液样本。用离心法分离乳细胞和乳脂层。用HRGC/HRMS分析奶油层中的二恶英(PCDD/F，共面多氯联苯)和非共面多氯联苯。提取外周血基因组DNA，进行CYP1Alm1、CYP1A1m2和GSTM1缺失基因分型。用实时荧光定量RT-PCR方法检测乳细胞中细胞色素P4501A1基因的表达。多氯二苯并二恶英、多氯二苯并呋喃、共面多氯联苯及其总和的几何平均浓度分别为7.3、3.8、5.2和16.8pg TEQ/g脂肪。CYP1A1 m2型的PCDF和DFCO(PCDD+PCDF+CoPCB)水平显著低于其他(异种或野生型)。这可能是由于微粒体酶活性增加所致。乳汁中的二恶英浓度与乳细胞中的CYP1A1基因的表达无明显相关性。在本研究中，乳汁细胞中的CYP1A1基因表达不能作为二恶英暴露的生物标志物。

Samples of breast milk and blood were obtained from 50 women at U Obstetrics and Gynecology Clinic within one week of childbearing with informed consent. The milk cells and cream layer were separated by centrifugation. Dioxins (PCDD/F, coplanar PCBs) and noncoplanar PCBs in the cream layer were analyzed by HRGC/HRMS. Genotyping of CYP1Alm1,CYP1A1m2 and GSTM1 null was performed from the genomic DNA extracted from peripheral blood. CYP1A1 mRNA expression in the milk cells was analyzed by real-time RT-PCR. The geometric mean concentrations of PCDDs,PCDFs, coplanar-PCBs and their sum were 7.3,3.8,5.2, and 16.8 pg TEQ/g fat, respectively. The levels of PCDF and DFCo (PCDD+PCDF+CoPCB) were significantly lower in the CYP1A1 m2 genotype than in others (hetero or wild). This might be explained by the increased microsomal enzyme activity. The expression of CYP1A1 mRNA in the milk cells was low and there was no significant correlation between dioxinconcentration in breast milk and CYP1A1 mRNA expression in the milk cells. CYP1A1 mRNA expression in the milk cells did not serve as a biomarker for dioxin exposure in the present study.