子痫前期孕妇外周血浆中高甲基化SIM2基因的含量变化

The Content Changes of Hypermethylated SIM2 Gene in Maternal Plasma with Preeclampsia

目的:通过检测高甲基化SIM2基因来分析游离胎儿DNA在正常妊娠孕妇及子痫前期孕妇外周血浆中含量的变化。方法:共收集114例外周血浆样本(包括健康未妊娠女性志愿者10例,产后48小时健康女性10例,正常妊娠孕妇57例,子痫前期孕妇37例),利用HpaⅡ、MspⅠ分别对提取的血浆DNA进行甲基化酶切反应后再进行实时荧光定量PCR反应,相对定量法检测高甲基化SIM2基因的含量。结果:①10例健康未妊娠女性志愿者及产后48小时健康女性外周血浆中均未检测出高甲基化SIM2基因;②57例正常妊娠孕妇中有43例检测出高甲基化SIM2基因,在不同妊娠阶段高甲基化SIM2基因含量的差异有统计学意义,高甲基化SIM2基因的含量在中期妊娠是早期妊娠的2.33倍,晚期妊娠是早期妊娠的5.28倍;③37例子痫前期孕妇中有36例检出高甲基化SIM2基因,高甲基化SIM2基因的含量在轻度子痫前期孕妇血浆中是正常晚期妊娠的3.05倍,在重度子痫前期孕妇中是正常晚期妊娠的6.32倍。结论:高甲基化SIM2基因是可靠的胎儿特异性标记,在孕妇外周血浆中高甲基化SIM2基因的含量随妊娠进展而增加,与孕周有关。高甲基化SIM2基因在子痫前期孕妇血浆中含量明显增加,能够反应子痫前期疾病的严重程度。

Objective：To investigate the content changes of cell-free fetal DNA in maternal plasma indifferent stages of normal and preeclampsia pregnancy by detecting the hypermethylated SIM2 gene. Methods：114 cases were selected in total,including 10 healthy non-pregnant woman volunteers,10 postpartum women in 48 hours,57 normal pregnant women and 37 in preeclampsia. Using Hpa II and Msp I for methylation sensitive restriction enzyme PCR and real-time fluorescence quantitative PCR to detect the content of hypermethylated SIM2 gene by relative quantitative assay. Reaults：①Hypermethylated SIM2 gene can not be detected in 10 healthy non-pregnant woman volunteers and 10 postpartum women in 48 hours;②43 of 57 normal pregnancy have been detected with hypermethylated SIM2 gene. Contents of hypermethylated SIM2 gene in each trimester aresignificantly different. The concentration of hypermethylated SIM2 gene in medium-term pregnancy is 2.33 times of early pregnancy while late pregnancy is 5.28 times of early pregnancy;③36 of 37 preeclampsia pregnancy women have been detected with hypermethylated SIM2 gene,the concentration of hypermethylated SIM2 gene in mild preeclampsia is 3. 05 times of normal late pregnancy,and severe preeclampsia is 6.32 times of the normal late pregnancy. Conclusions ：Hypermethylated SIM2 gene is a reliable fetal-specific marker,and the concentration of hypermethylated SIM2 genes in maternal plasma increases with pregnancy progress. Increased concentration of hypermethylated SIM2 genes in maternal plasma can reflect the severity of the preeclampsia.