The Expression Of PROK1and PR In Endometrium Of Patients With RIF In Mid-luteal Phase

Back groundRepeated implantation failure（RIF） means that patients are still notpregnant after transplantation of high quality embryos more than three times. WhichIs one of the most difficult problems in the field of reproduction. Its causes can bedivided into three parts： The decrease of embryo quality、 The decrease ofendometrial receptivity in mid-luteal phase、disorder of hormone and immune. Asthe development of cryopreservation of embryos、 controlled ovarianhyperstimulation, there is significant improvement in the quality ofembryos,however,the researches about endometrial receptivity are still in slowprogress. According to domestic and foreign research，among the reasons for thefailure of transplanted，endometrial factors accounted for66.7%。Endometrial receptivity means that The ability of endometrium to acceptembryos. In the mid luteal phase，progesterone Is able to induce endometrium into acertain sate That allows blastocyst positioning, adhesion, invasion,and make it turninto decidua Under the action of the blastocyst. In this process,， there are a lot ofnew blood capillaries generated,Various cytokines closely related to endometrialreceptivity and embryo implantation interact coordinately, which prepare for thearrival of the embryo.If new blood capillaries generate Insufficiently or cytokinesclosely related to endometrial receptivity and embryo implantation expressabnormally in the process of turning into state of receptivity. Then endometrialreceptivity will be affected adversely. Which ultimately lead to failuretransplantation. Prokineticin-1(PROK1) is a kind of secreted protein discovered in recent years.Previous studies have found that：PROK1mainly express in the organs which secretsteroid hormone, such as ovaries, testes,adrenal glands steroid, and so on. Recentstudies have found that：in some non-steroid secreted organs, for example:uterus,there are also a considerable number of expression. The expression of PROK1inuterus is mainly located on the endometrium, which changes periodically asmenstrual cycle and shows a peak expression in mid-luteal phase. Studies haveshown that: PROK1Is a new marker of endometrial receptivity, which play aregulatory role on generating endometrial capillaries by selectively acting onvascular endothelial cells of endometrium, and regulate some cytokines related toendometrial receptivity such as leukemia inhibitory factor, IL-8, IL-11. From theseabove, we can see that normal expression of PROK1is inseparable for endometrialreceptivity.Transformation of endometrium from proliferative phase to secretory phase(mid-luteal phase) is a prerequisite for implantation. The whole process oftransformation is induced by progesterone. In mid luteal phase, under the effects ofprogesterone, we can observe that a lot of pinopodes, hypertrophy of the prostateepithelial cells, decidual cells appear on the endometrium, all the things aboveprovide preparation for embryo implantation. From these above, we can see that，progesterone play an important role on inducing transformation from proliferativephase to secretory phase and regulating the process of implantation. Progesteroneexert its Biological effects by way of binding its receptor, therefore，lack of eitherprogesterone or progesterone receptor will decline the biological effects ofprogesterone. Nowadays, progesterone is used routinely as support after ovulationto the patients under treatment of IVF-ET，the expression of PR in the mid-lutealphase is especially important， low expression of PR will directly affect theconstruction of endometrium receptivity and the process of implantation.In summary，PROK1and PR play an important role on construction ofendometrium receptivity and process of implantation. ObjectiveTo observe expression of Prokineticin-1(PROK1) and progesterone receptor(PR) inhuman endometrium of patients with Repeated implantation failure(RIF) inmid-luteal phase.Material and Methods1、Patients21patients with RIF were recruited in Guangdong Women and Children Hospitalfrom August2013to April2014(study group), and23patients who were pregnantat least once(control group).2、 Method of experiment(1)Judge the endometriums by way of Hematoxylin and eosin stain toobservewhether they belong to mid-luteal phase or not(2)Detect the mRNA expression of PROK1and PR by way of Real timefluorescent quantitative PCR（3）Detect the protein expression of PROK1and PR by way of IHCResults1、All of44cases were detected in mid-luteal phase.2、The mRNA of PROK1and PR were detected in all cases. The mRNAexpression level of PROK1in study group (0.21±0.20) was significantly lowerthan that of control group (0.36±0.18),and there was significant difference inPROK1mRNA expressions in endometrium between study group and control group;The mRNA expression level of PR in study group (2.49±0.87) was significantly lower than that of control group (4.28±1.22) and there was significant difference inPR mRNA expressions in endometrium between study group and control group.3、The protein of PROK1and PR were detected in all the cases, the protein ofPROK1was observed to be localized in epithelial cells and stromal cells, the proteinof PR was detected in endometrial glandular epithelial cells and stromal cells.Theprotein expression level of PROK1in study group (0.016±0.006) was significantlylower than that of control group (0.021±0.004),and there was significant differencein PROK1protein expressions in endometrium between study group and controlgroup; The protein expression level of PR in study group (0.27±0.03) wassignificantly lower than that of control group (0.34±0.02) and there was significantdifference in PR protein expressions in endometrium between study group andcontrol group.ConclusionThe lower expression level of PROK1and PR in endometrium of RIF patients inmid-luteal phase are involved in the pathogenesis of RIF.