Despite encouraging advances in fertility technology, the success rate of an ongoing pregnancy is relatively low and predominantly associated with implantation failure. Inflammatory responses are beneficial in the fetomaternal interface and supposedly accelerate the chances for successful implantation. The current study aims to determine the effect of Toll‐like receptor 4 (TLR4) overexpression in mouse blastocysts via Let‐7a downregulation using intracytoplasmic sperm injection‐sperm‐mediated gene transfer on embryo attachment rate. The pLenti‐III‐GFP‐miR‐Off‐Let‐7a vector was transmitted to oocytes derived via in vitro maturation (IVM) and in vivo oocytes by using NaOH‐treated spermatozoa. Let‐7a and TLR4 expression levels were evaluated by quantitative real‐time polymerase chain reaction (qRT‐PCR), immunocytochemistry, and western blot analysis in both oocytes and embryos. Blastocyst adhesion on the endometrial cells was monitored by microscopic analysis. qRT‐PCR results showed that Let‐7a expression decreased in the IVM (GV‐MII) oocytes compared to the in vivo oocyte (MII) group (p < .05). TLR4 showed a higher expression in GV‐MII oocytes at both the gene and protein levels (p < .05). Following anti‐miR‐Let‐7a transmission, the TLR4 expression level was significantly upregulated in embryos compared with the control groups (p < .05). Attachment and migration of trophoblasts cells towards endometrial cells dramatically increased compared to the control group (p < .05). Based on our results, we concluded that Let‐7a might mediate embryo attachment through regulation of TLR4 expression levels.

中文翻译：

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通过抗miR-Let-7a对Toll样受体4的上调增强了小鼠囊胚对子宫内膜细胞的附着。

尽管在生育技术方面取得了令人鼓舞的进步，但正在进行的妊娠的成功率相对较低，并且主要与植入失败有关。炎症反应在胎儿母体界面中是有益的，并且据认为可以加快成功植入的机会。本研究旨在通过使用胞浆内精子注射-精子介导的基因转移通过Let-7a下调来确定Toll样受体4（TLR4）在小鼠胚泡中的过表达对胚胎附着率的影响。使用NaOH处理的精子将pLenti-III-GFP-miR-Off-Let-7a载体转移至通过体外成熟（IVM）衍生的卵母细胞和体内卵母细胞。通过实时定量聚合酶链反应（qRT-PCR），免疫细胞化学，和卵母细胞和胚胎的蛋白质印迹分析。通过显微镜分析监测囊肿在子宫内膜细胞上的粘附。qRT-PCR结果显示，与体内卵母细胞（MII）组相比，IVM（GV-MII）卵母细胞中Let-7a的表达降低了（p  <.05）。在基因和蛋白质水平上，TLR4在GV-MII卵母细胞中都有较高的表达（p  <.05）。抗miR‐Let‐7a传播后，与对照组相比，胚胎中TLR4的表达水平显着上调（p  <.05）。与对照组相比，滋养层细胞向子宫内膜细胞的附着和迁移显着增加（p  <.05）。根据我们的结果，我们得出结论，Let-7a可能通过调节TLR4表达水平来介导胚胎附着。