Endometrium Morphology Analysis And Expressions Of Survivin And VEGF In The Endometrium Of Peri-implantation Mice

Objective①To observe the histological changes in the endometrium of unpregnant (estrous stage), pregnant and pseudopregnant mice in the peri-implantation ;②To observe the ultrastructure changes in the endometrium of unpregnant (strous stage) and pregnant mice in the peri-implantation;③To study the expressions and distributions of Survivin and VEGF in the endometrium of unpregnant (estrous stage), pregnant and pseudopregnant mice in the peri-implantation;④To explore the link between the expressions of Survivin and VEGF in the endometrium of pregnant mice in the peri-implantation. Methods We took mature and nulliparous Kunming female mice as subjects and three Kunming adult female mice were caged with a normal or a vasoligation male overnight. In the following morning, females were checked for the presence of a vaginal sperm plug. The day of vaginal plug was regarded as day 1 of pregnancy or pseudopregnancy. Firstly, 60 pregnant mice and 60 pseudopregnant mice of day 3-6 were put to death through cervical vertebrae luxation, and then the uteri were disemboweled and the unpregnant mice uteri were (estrous stage) taken as controls. The uteri were fixed in 4% paraformaldehyde. Hematoxylin-Eosin(HE) staining was used to observe histological structures in the endometrium of pregnant and pseudopregnant mice; Ultrastructure changes in the endometrium of pregnant mice were observed by transmission electron microscope(TEM); Immunohistochemi- cal SP staining was used to measure the expression of Survivin and VEGF, respectively. Pictures were taken by microscopic imaging system and then the results of HE and immunohistochemical staining were analysed by computer. Results①HE staining showed that structural changes of mice endometrium exhibited the developmental tendency on day 3-6 of pregnancy. The amounts of uterine glands increased gradually, and the endometrium showed physiological edema. Moreover, the intercellular space of stroma cells became augmented, and blood vessels proliferation. The most obvious changes appeared on day 4-5 of pregnant mice;②Under TEM, cell organs in luminal epithelium, glandular epithelium and stroma cells in endometrium on day 3-6 of pregnancy were more than those in unpregnant mice(estrous stage). Abundant Mi, RER, SG and so on in luminal epithelium and glandular epithelium and interstitial edema were observed on day 4-5 of pregnancy. Moreover, stroma cells got hypertrophy, abound with affluent glycogen and lipid droplet intracytoplasm;③The results of immunohistochemisty revealed that the expressions of the Survivin were distributed differently in the endometrial luminal, glandual epithelium and stromal cells of unpregnant(estrous stage), pregnant and pseudopregnant mice. The expression of the Survivin reached the peak on day 5-6 of pregnant mice; The VEGF was expressed in the endometrial luminal epithelium and stromal cells of unpregnant(estrous stage), pregnant and pseudopregnant mice, and the most VEGF appeared on day 4-5; The expressions of Survivin and VEGF in pseudopregnant mice were the same as the one in the pregnant mice on day 3-4. But on day 5-6, the expression of these in pseudopregnant mice was much weaker than them in pregnant mice;④The mean optical densities (MOD) of Survivin and VEGF in pregnant mice on day 3-6 were calculated through image analysis. The data by SPSS software indicated that there was a positive correlation between the expressin of Survivin and VEGF in the peri-implantation endometrium of pregnant mice. Conclusions①The morphological changes in the endometrium of pregnant mice exhibted a dynamic changing tendecy and the prominent changes appeared during the window of implantation;②The continued expression of Survivin in the endometrial luminal and glandual epithelium and stromal cells of pregnant mice on day 3-6 suggested that Survivin might play an important role in the process of the embryo implantation in mouse;③The VEGF was expressed continuously in mouse endometrium on day 3-6 of pregnancy. It suggested that VEGF might play a key role in the process of the embryo implantation in mouse;④In the endometrium of pseudopregnant mice, the laws revealed that the expressions of Survivin and VEGF were regulated not only by matemal hormone, but also by the implanted embryos and other chemical signals;⑤The expressions of Survivin and VEGF have a positive correlation in the peri-implantation endometrium of pregnant mice which suggested that Survivin and VEGF collaboratively were involved in the process of implantation.