目的·探讨抑制神经元细胞和雌性大鼠下丘脑弓状核中甲状腺转录因子1（thyroid transcription factor 1，Ttf1）基因的表达对亲吻素（Kiss1）和促性腺激素释放激素（gonadotropin-releasing hormone，GnRH）基因表达的影响。方法·针对大鼠Ttf1基因的mRNA序列分别设计3对特异性的干扰序列（TTF1-shRNA1、TTF1-shRNA2、TTF1-shRNA3），包装成慢病毒质粒。以神经元细胞ND7-23为体外模型，采用real-time PCR及Western blotting技术筛选干扰效率最高的慢病毒质粒（LV-TTF1-shRNA），转染72 h后检测Kiss1和GnRH基因的表达。将LV-TTF1-shRNA和空载质粒注射到21日龄雌性大鼠的下丘脑弓状核内，分别在幼年期（25日龄）、青春发育早期（35日龄）、成年期（42日龄）检测弓状核内Kiss1和GnRH基因的表达变化并观察雌鼠的阴门开放时间。结果·慢病毒质粒转染ND7-23细胞72 h后，LV-TTF1-shRNA2组、LV-TTF1-shRNA3组的Ttf1 mRNA及蛋白表达均显著减少（均P<0.05），其中LV-TTF1-shRNA3干扰效果最佳。采用LV-TTF1-shRNA3抑制ND7-23细胞中Ttf1表达后，Kiss1和GnRH基因的mRNA表达均显著降低（均P<0.05）。雌鼠弓状核内双侧显微注射LV-TTF1-shRNA3后，25日龄、35日龄、42日龄大鼠弓状核Kiss1和GnRH的mRNA均显著降低（均P<0.05），35日龄和42日龄时KISS1蛋白水平明显降低，且雌鼠阴门开放时间延迟。结论·在细胞水平和雌性大鼠弓状核内抑制Ttf1基因表达均使得Kiss1和GnRH基因表达显著下调，也导致雌鼠阴门开放时间明显延迟。

Objective · To explore the effects of inhibiting thyroid transcription factor 1 (Ttf1) expression on Kiss1 and gonadotropin-releasing hormone (GnRH) expressions in neuronal cells and hypothalamic arcuate nucleus (ARC) of female rats. Methods · Three shRNAs (TTF1-shRNA1, TTF1-shRNA2, and TTF1-shRNA3) interference sequences were designed for rat Ttf1 gene and were constructed into lentiviral vectors. The efficiency of LV-TTF1-shRNA was detected by real-time PCR and Western blotting in neuronal cell line ND7-23. And the expressions of Kiss1 and GnRH were tested 72 h after transfection. Moreover, LV-TTF1-shRNA or the blank lentiviral vector was injected into 21-day female rats’ ARC. Kiss1 and GnRH expressions were detected at the juvenile (25-day), early puberty (35-day) and adult (42-day) stages. Meanwhile, vaginal opening time of the rats was recorded. Results · Seventy-two hours after lentivirus transfection in ND7-23 cells, the mRNA and protein expressions of Ttf1 decreased significantly in LV-TTF1-shRNA2 group and LV-TTF1-shRNA3 group (all P<0.05), particularly in LV-TTF1-shRNA3 group. The expressions of Kiss1 and GnRH mRNA reduced significantly after LV-TTF1-shRNA3 being transfected in ND7-23 cells (both P<0.05). After injection of LV-TTF1-shRNA3 in female rats’ ARC, mRNA abundance of Kiss1 and GnRH showed evident reduction at 25-day, 35-day and 42-day stages (all P<0.05). And KISS1 protein reduced significantly at 35-day and 42-day stages. Female rats transfected with LV-TTF1-shRNA3 showed delayed vaginal opening. Conclusion · Inhibition of Ttf1 gene expression not only significantly reduces the expression of Kiss1 and GnRH in neuronal cells and female rats’ ARC, but also causes female rats vaginal opening delay.