宫内镉暴露对新生儿全基因组DNA甲基化水平的影响

Effect of cadmium exposure in utero on global DNA methylation of newborns

[目的]探讨宫内镉暴露对新生儿全基因组DNA甲基化水平的影响。[方法]选取2011—2012年在某妇幼保健院分娩的300名产妇作为研究对象,分娩时收集新生儿脐动脉血,采用ICP/MS法检测脐动脉血中镉的质量浓度,LC-MS/MS法检测脐动脉血中全基因组DNA甲基化水平。采用Spearman相关分析法和多元线性逐步回归法分析两者之间的关系。[结果]新生儿脐动脉血中镉的质量浓度最小值为0.02μg/L,最大值为2.61μg/L,四分位数为0.08、0.16、0.30μg/L。Spearman相关分析显示,脐动脉血镉的质量浓度与DNA甲基化水平无相关性(r=-0.106,P=0.068)。多元线性逐步回归分析结果显示,排除混杂因素后,脐动脉血镉质量浓度与全基因组DNA甲基化水平呈负相关(P<0.05)。[结论]宫内镉暴露可能会使新生儿全基因组DNA甲基化水平降低。

[ Objective ] To explore the effect of cadmium exposure in utero on global DNA methylation of newborns. [ Methods ] A total of 300 puerperae who gave birth in a selected maternal and child health center from 2011 to 2012 were enrolled in the study to collect umbilical arterial blood samples. Cadmium concentrations in umbilical arterial blood were detected by ICP/MS. Global DNA methylation levels in umbilical arterial blood were quantified by LC-MS/MS. The correlations between the cadmium concentration and the global DNA methylation levels were assessed by Spearman correlation analysis and multiple linear step-wise regression analysis. [ Results ] The cadmium concentrations were 0.02-2.61 μg/L in the umbilical arterial blood samples, and the quartiles were 0.08, 0.16, and 0.30 μg/L, respectively. No correlation was observed between the umbilical arterial blood cadmium levels and the global DNA methylation by Spearman correlation analysis （r=-0.106, P=0.068）. The results of multiple linear regression analysis showed that after excluding selected confounding factors the umbilical arterial blood cadmium level was negatively correlated to the global DNA methylation level （P〈 0.05）. [ Conclusion ] In utero cadmium exposure might be associated with lower global DNA methylation level in newborns.