Study of the dynamic expression of Meis1 in mice

Background: Aggressive embryo and receptive endometrium are necessary for successful implantation. On this time endometrium transformates to receptive state, which permits embryonic implantation. Studies about embryonic implantation and endometrial receptivity are always a hot spot in the field of reproductive medicine. Objective: To investigate the expression pattern of Meis1 during peri-implantation in mice endometrium. Materials and Methods: Mice for experiment were raised in SPF environment. The mice were mated with a female/male ratio of 2:1. The female mice with detected plugs were regarded as pregnant day 1 (pd1). Endometrial tissues were collected respectively on pd1, pd2, pd4, pd5 and pd6. Immunohistochemistry was used to detect the location of Meis1 in mice endometrium. The expression level of mRNA and protein of Meis1 were further detected using Quantitative PCR and Western blotting, respectively. Results: We found that Meis1 is located in the cytoplasm and membrane of endometrial glandual epithelium cells and the nucleus of endometrial stromal and decidual cells. Both Quantitative RT-PCR and western blotting showed that Meis1 expressed regularly in mice endometrium. Meis1 mRNA expressed weakly on pd1, then significantly increased on pd4 (p=0.018), and achieved to a peak on pd5 (p=0.0012), it showed a decrease trend on pd6. Meis1 protein expressed weakly on pd1 and pd2, then significantly increased on pd4 and pd5 (p=0.0019), it showed a decrease trend on pd6 Conclusion: Meis1 is dynamically expressed in mice endometrium during peri-implantation. The time that Meis1 expression reaches its peak value is coincident with the implantation window, which implied that Meis1 is closely related with embryonic implantation.