中文摘要：

目的 研究轴突导向因子netrin-1基因沉默对胎盘血管生成的影响.方法 应用RNA 干扰技术分别沉默netrin-1基因在人脐静脉内皮细胞（HUVEC）和孕鼠胎盘组织中的表达;用四甲基偶氮唑蓝（MTT）比色法检测细胞活性;克隆形成实验检测细胞增殖能力;细胞迁移实验检测细胞迁移能力;小管形成实验检测细胞管腔形成能力;观察胎鼠体质量;CD34因子的免疫组化链霉亲和素-生物素-过氧化物酶复合物（SABC）法检测孕鼠胎盘的微血管密度.结果 （1）HUVEC：沉默netrin-1基因后,HUVEC细胞活性受到抑制,克隆形成率由（69±6）%降至（46±5）%,迁移细胞数由（86±17）个降至（46±13）个,小管形成的分支点数由（37±9）个降至（17±5）个,HUVEC的netrin-1基因沉默前后比较,差异均有统计学意义（P＜0.05）.（2）孕鼠胎盘组织：沉默孕鼠胎盘组织netrin-1基因后,胎鼠体质量由（2.39±0.17）g降至（2.12±0.10）g,胎盘微血管密度由（258±38）条/mm2降至（197±32）条/mm2,孕鼠胎盘组织netrin-1基因沉默前后比较,差异均有统计学意义（P＜0.05）.结论 沉默netrin-1基因,可以抑制体外HUVEC的细胞活性及增殖、迁移和管腔形成能力,同时使体内胎盘组织的血管生成能力下降.netrin-1是重要的促胎盘血管生长基因.

英文摘要：

Objective To study influence on angiogenesis of placenta by gene silencing of netrin-1.Methods Netrin-1 gene in human umbilical vein endothelial cells（HUVEC）and placenta of pregnant rats were silenced by RNA interference.The following methods were used in this study,including the phenytetrazoliumromide（MTT）for viability,clone formation for proliferation,transwell for migration,and tube formation for angiogenesis in vitro.The change of fetal growth was recorded.Placental microvessel density in pregnant rats was measured by immunohistochemical CD34 staining in vivo.Results （1）HUVEC：viability and proliferation of HUVEC were remarkably inhibited by gene silencing of netrin-1.which number of clone formation,migration cell,tube formation were from（69±6）%,86±17,37±9 decreased to（46±5）%,46±13 and 17±5（P〈0.05）respectively.（2）Placenta of pregnant rats：after netrin-1gene silenced,fetal weight were decreased from（2.39 ±0.17）g to（2.12±0.10）g（P〈0.05）.Placental microvessel density was decreased from（258±38）/mm2 to（197±32）/mm2 in vivo（P〈0.05）.Conclusions Gene silencing of netrin-1 could inhibit viability,proliferation,migration,tubal formation of HUVEC and angiogcnesis of placenta.Netrin-1 plays an important role in regulating angiogenesis in placenta.