子痫前期孕妇胎盘组织中生长阻滞和DNA损伤45α基因的表达变化及其临床意义

摘要

目的 通过检测子痫前期孕妇胎盘组织中生长阻滞和DNA损伤45α(Gadd45α)基因的定位及表达变化,探讨其与子痫前期发病的关系.方法 选择2009年9月至2010年3月在重庆医科大学附属第一医院住院分娩的36例子痫前期孕妇为研究对象,按病情分为子痫前期轻度组(20例),子痫前期重度组(16例),另以同期择期行足月剖宫产术的18例健康孕妇为对照组.3组孕妇分娩后取胎盘组织标本,采用免疫组化链霉菌抗生物素蛋白-过氧化物酶连接(SP)法检测各组孕妇胎盘组织中Gadd45α蛋白的定位及分布,采用逆转录(RT)-PCR技术检测各组孕妇胎盘组织中Gadd45α mRNA表达水平,采用蛋白印迹(western blot)技术检测各组孕妇胎盘组织中Gadd45α蛋白的表达水平.结果 (1)子痫前期轻度组及重度组胎盘组织中均有Gadd45α蛋白表达,主要定位于胎盘滋养层细胞的胞质及胞核中,血管内皮细胞及少量间质细胞胞核也可见阳性染色;对照组胎盘组织中阳性染色较弱,且仅见于胎盘滋养层细胞中,血管内皮细胞中未见阳性染色.(2)子痫前期重度组及轻度组胎盘组织中Gadd45αmRNA表达水平分别为0.75±0.07及0.44±0.13,明显高于对照组的0.18±0.04,分别比较,差异均有统计学意义(P＜0.05);子痫前期重度组Gadd45α mRNA表达水平与子痫前期轻度组比较,差异也有统计学意义(P＜0.05).(3)子痫前期重度组及轻度组胎盘组织中Gadd45α蛋白表达水平分别为1.34±0.17及0.65±0.15,两组比较,差异有统计学意义(P＜0.05);两组也明显高于对照组的0.22±0.11,分别比较,差异均有统计学意义(P＜0.05).结论 子痫前期患者胎盘组织中Gadd45α mRNA和蛋白表达水平均明显高于健康孕妇,并且随子痫前期患者病情加重其表达上调;Gadd45α定位在与子痫前期发生密切相关的胎盘滋养层细胞中,Gadd45α基因可能参与了子痫前期的发生与发展.%Objective To evaluate the expression and location of the growth arrest and DNA damage 45 alpha(Gadd45α)gene in human placenta and explore the relationship between Gadd45α and preeclampsia(PE).Methods Thirty-six women with preeclampsia who delivered from September 2009 to March 2010 in the First Affiliated Hospital of Chongqing Medical University were chosen as the study objects.They were classified into mild group( n = 20), severe group( n = 16) and elective term cesarean sections group without previous onset of labor and perinatal complications ( control group, n = 18 ).Placentas were collected after they delivered and immunohistochemical streptravidin-biotin peroxidase(SP) method and histoscore were employed to detect the expression and localization of Gadd45α protein.Gadd45α mRNA level was determined by reverse transcription polymerase chain reaction (RT-PCR) technique and western blot analysis was used to quantify Gadd45α protein expression level.Results (1)Gadd45α protein was detectable in placenta tissues of the mild and severe groups, mostly located in cytoplasm and nuclei of trophoblast, plus nuclei of vascular endothelial cells and a few stromal cells; whereas placenta tissues of control group showed weak staining, and only detectable in trophoblast, undetectable in vascular endothelial cells.(2)The Gadd45α mRNA levels in placenta tissues of the severe and mild groups were 0.75 ±0.07 and 0.44±0.13, respectively, significantly higher than that in control group (0.18 ±0.04, P ＜0.05);compared with mild group, Gadd45α mRNA level was significantly higher in severe group( P ＜ 0.05 ).(3)The Gadd45α protein levels in placenta tissues of the severe and mild groups was 1.34 ±0.17 and 0.65 ±0.15, respectively, compared with mild group, Gadd45α protein level was higher in severe group (P ＜0.05); they were both significantly higher than that in control group ( 0.22 ± 0.11, P ＜ 0.05 ).Conclusions Gadd45α mRNA and protein levels in placenta tissues of patients with preeclampsia are higher than that of normotensive women, and up-regulated with aggravation of preeclampsia; the Gadd45α protein is located in trophoblast cells, which are closely related to pathogenesis of preeclampsia.These results indicate that Gadd45α plays an important role in the pathogenesis and progression of preeclampsia.