中文摘要：

目的：观察单次剂量RU486对受孕小鼠在着床窗期子宫内膜表面胞饮突表达的影响。方法：将受孕小鼠随机分为正常组、处理组1、处理组2、处理组3和处理组4，正常组不作任何处理，后4组分别在妊娠第1～4天上午7～8时皮下注射米非司酮0．1mg。各组分别于第4天晚21：30-22：00时和第5天上午9：30～10：00时颈部脱臼处死部分小鼠，采用扫描电镜观察在这两个时间点各组小鼠子宫内膜表面胞饮突的表达。结果：第1天给予米非司酮，子宫内膜表面可观察到发育中的胞饮突以及发育完全的胞饮突，但数量较正常明显减少；第2天给予米非司酮，仅能观察到少量发育中的胞饮突，未见到发育完全的胞饮突；第3天给予米非司酮，亦仅能观察到发育中的胞饮突；第4天给予米非司酮，当晚不同发育阶段的胞饮突仅在局部少量表达，至第5天上午胞饮突表达完全消失。结论：第1～4天清早皮下单次注射RU486，均明显影响或抑制子宫内膜表面胞饮突的表达以及子宫内膜接受性的建立，从而最终影响了胚胎着床。

英文摘要：

OBJECTIVE To investigate the effect of a single dose of mifepristone on pinopodes expression on the endometrial surface during the window of implantation in mice. METHODS The pregnant mice in the treated groups 1, 2, 3 and 4 received mifepristone injection （0. 1 mg） subcutaneously between 07. 00 and 08. 00 hrson Pdl （the day displaying of vaginal plug）, Pd2, Pd3 and Pd4, respectively. The pregnant mice in the non-treated group were used as normal control group. Randomly, uterine horns of two mice from each group were collected between 21：30 and 22：00 hrs on Pd4 and of other two mice of the same group between 09：30 and 10：00 hrs on Pd5. Pinopodes expression on endometrial surface was observed using scanning electron microscopy （SEM）. RESULTS When mifepristone was given on Pd1, developing and fully developed pinopodes could be observed, however, the expression was reduced when compared to control group. When mifepristone was given on Pd2, only scanty developing pinopodes could be observed, but not fully developed pinopodes. When mifepristone was administered on Pd3, developing pinopodes could be seen. When mifepristone was administered on Pd4, pinopodes were locally expressed and with different developmental stages in the first biopsy, but no pinopodes were observed in the second. CONCLUSION These findings indicate that administration of a single dose of RU486 subcutaneously on Pd1, Pd2, Pd3 and Pd4 respectively appears to inhibit development and maturation of endometrium, as assessed by pinopode expression, thus affecting the establishment of embryo implantation.