Expression of Epidermal Growth Factor Receptor in Human Endometrium, Decidua and Trophoblast Cells
ZHANG Lifeng*, SU Yingkuan, GAI Ling*, et al.*Shandong Institute of Family Planning Research, Jinan 250002
【Abstract】ObjectiveTo study the expression of epidermal growth factor receptor (EGFR) expression in human normal endometrium, decidua and trophoblast cells of early pregnancy, and to explore the effect of EGFR on cell proliferation and development.MethodsTo localize the EGFR expression in glandular and stromal cells of normal endometrium, decidua with immunohistochemical method(ABC), and to analyse the related quantity of EGFR mRNA by RT-PCR method.ResultsThere were EGFR expression in both normal endometrium and decidua. EGFR protein located on cell membrane, nuclear membrane and in the cytoplasm as well, and located in the neuclear of glandular and stromal cells in decidua. The expression of EGFR in glandular cells was significantly stronger than that in the stroma (P<0.05), while there was no difference of EGFR expression in the glands during the menstrual cycle (P>0.05). However, the expression of EGFR in the glands of decidua was significantly higher than that in the proliferative and secretory endometrium (P<0.05). The intensity of staining in stromal cells listed in order from the strongest was early decidua>secretory endometrium>proliferative endometrium, the differences were significant (P<0.05). The related quantity of EGFR mRNA expression in proliferative, secretory endometrium, decidua and trophoblasts were: 0.531±0.061, 0.594±0.121, 0.732±0.032, 0.828±0.034, respectively. There was no difference during the menstrual cycle, but that in the decidua and trophoblasts were significantly higher than that in the proliferative and secretory endometrium (P<0.05), and that in the trophoblasts was the highest.ConclusionEGFR expression was present in the proliferative and secretory endometrium, decidua and trophoblasts of early pregnancy, and it was significantly higher in the decidua and trophoblasts than that during the menstrual cycle.
【Key words】Receptors, epidermal growth factor-urogastroneEndometriumImmunohistochemistryPolymerase chain reactionDecidua
表皮生长因子(EGF)是由53个氨基酸组成的单链多肽,是一种促有丝分裂物质。近年来研究发现,EGF受体(EGFR)在人子宫内膜中有表达[1],证明EGF及EGFR在子宫内膜细胞增殖及分化中发挥作用。我们应用免疫组织化学方法对EGFR在子宫内膜及早孕蜕膜中的表达进行定位分析,应用逆转录-聚合酶链反应(RT-PCR)技术对EGFR mRNA在子宫内膜、早孕蜕膜及滋养细胞中的表达进行定量分析,探讨其与子宫内膜细胞分化、增殖的关系。
资料及方法
一、标本来源
1.正常子宫内膜标本:1996年10月至1997年10月在山东省立医院妇产科,因子宫肌瘤行子宫切除的子宫内膜组织,共58例。年龄在34~45岁之间,其中32例为增生期,26例为分泌期。术前3个月未用激素治疗,月经规律,病理检查证实为正常子宫内膜。取出的内膜一部分立即投入液氮中保存以提取RNA,另一部分用10%甲醛固定。
2.早孕蜕膜标本:1996年10月至1997年10月在山东省立医院妇产科门诊行人工流产术早孕蜕膜组织,共26例。年龄22~30岁,月经规律,经尿妊娠实验及B超检查证实为妊娠者,术前2周未用激素治疗。分别取蜕膜及绒毛组织,标本处理同子宫内膜。
二、方法
1.免疫组化的组织标本经固定常规包埋、切片厚5 μm,分别行HE及免疫组化ABC法染色。切片常规脱蜡、水化,0.2%胃蛋白酶(美国Sigma公司产品)消化;3%过氧化氢封闭内源性过氧化物酶活性;10%小牛血清37℃下作用20分钟,以减少非特异性染色;滴加兔抗人EGFR IgG多克隆抗体及免疫组化ABC试剂(购自北京中山生物技术有限公司,为美国Santa Cruz公司产品),按说明书操作。另以磷酸盐缓冲液(PBS)代替一抗作为阴性对照。阳性判断为细胞核、胞浆或胞膜染成棕黄色,每张切片计数5个高倍视野,根据染色程度将阳性结果分为(+):轻度着染;(++):中度着染;(+++):重度着染。
2.RT-PCR[2]:(1)RNA的提取:从液氮 中取出各种组织100 mg,加入1 ml TRIzol(美国GIBCO公司产品),按说明书操作。定量RNA并调成1 μg/μl。(2)逆转录:在20 μl的反应体系中加入RNA 2 μl,5×buffer 4 μl,DTT(Promega)0.5 μl,dNTPs(25 mmol/L)0.5 μl(Promega), RNasin(Promega)0.5 μl,Moloney鼠白血病病毒(MMLV)逆转录酶(200 μl/μl)2 μl,寡(dT)12~18引物2 μl,加水至20 μl,混匀,37℃作用60分钟,95℃作用5分钟,灭活逆转录酶,立即冰浴冷却。(3)PCR反应[3]:将逆转录产物进行扩增[4]。EGFR 5′端引物序列为:5′-CGCTGCTGGCTGCGC- TCTG-3′(224~242);3′端引物序列为:5′-AGCCACC- TCCTGGATGGTC-3′(426~444)。内参照激活素(β-actin)5′端引物序列为5′-AAGGTGACCCAGAT- CATGTTTGAG-3′(393~416),3′端引物序列为5′-AGGAGGAGCAATGATCTTGATCTT-3′(1017~1040)。20 μl的反应体系中加入:10×buffer 2 μl, 25 mmol/L mcl 21.6 μl, 25 mmol/L dNTPs 1.5 μl,β-actin引物各0.4 μl,EGFR引物各0.4 μl,2U/μl Tag酶0.4 μl,反转录产物1.5 μl,加去离子水至20 μl。94℃ 30秒,55℃ 1分钟,72℃ 1分钟,共30个循环。(4)电泳及定量分析:PCR产物加缓冲液,1.2%琼脂糖电泳(电压为100V),电泳后拍照。Pharmacia LKB Ultrascan XL图像分析仪扫描扩增的EGFR及β-actin条带,EGFR量以EGFR峰值的面积与β-actin面积之比表示。以上所用器皿及配试剂所用的去离子水,均经过焦碳酸二乙脂(DEPC,美国CIBCO公司产品)处理。
三、统计学方法
采用秩和检验,χ2分析,t检验。
结果
一、EGFR在正常子宫内膜及早孕蜕膜组织中的定位和表达
EGFR存在于正常子宫内膜及早孕蜕膜腺体及间质细胞的细胞膜、核膜及胞浆内,分布均匀,在早孕蜕膜,EGFR还位于腺体、间质细胞核内。(图1~4)。正常子宫内膜EGFR的表达为腺体部位高于间质部位,两者差异有显著性(P<0.05),但早孕蜕膜腺体及间质的表达不明显(P>0.05),见表1。
1增生期子宫内膜上皮间质细胞染色较弱。免疫组化ABC×200
2早分泌期子宫内膜腺上皮细胞着色较深,间质细胞着色较弱,着色位于细胞浆内。免疫组化ABC×200
3晚分泌期子宫内膜腺上皮细胞及间质细胞均呈深染,染色位于腺上皮、间质细胞浆内及间质细胞胞核内。免疫组化ABC×200
4早孕蜕膜腺上皮细胞及间质细胞均呈深染,染色位于腺上皮、间质细胞胞浆内、胞膜、胞核内枋膜。免疫组化ABC×400
表1EGFR在正常子宫内膜及早孕蜕膜组织中
的定位表达(例数)
