EGF increases expression and activity of PAs in preimplantation rat embryos and their implantation rate

BACKGROUND: Embryo implantation plays a major role in embryogenesis and the outcome of pregnancy. Plasminogen activators (PAs) have been implicated in mammalian fertilization, early stages of development and embryo implantation. As in-vitro developing embryos resulted in lower implantation rate than those developed in-vivo we assume that a reduced PAs activity may be involved. In the present work we studied the effect of EGF on PAs activity, quantity and embryo implantation. METHODS: Zygotes were flushed from rat oviducts on day one of pregnancy and grown in-vitro in R1ECM supplemented with EGF (10 ng/ml) and were grown up to the blastocyst stage. The control groups were grown in the same medium without EGF. The distribution and quantity of the PAs were examined using fluorescence immunohistochemistry followed by measurement of PAs activity using the chromogenic assay. Implantation rate was studied using the embryo donation model. RESULTS: PAs distribution in the embryos was the same in EGF treated and untreated embryos. Both PAs were localized in the blastocysts' trophectoderm, supporting the assumption that PAs play a role in the implantation process in rats. EGF increased the quantity of uPA at all stages studied but the 8-cell stage as compared with controls. The tissue type PA (tPA) content was unaffected except the 8-cell stage, which was increased. The activity of uPA increased gradually towards the blastocyst stage and more so due to the presence of EGF. The activity of tPA did not vary with the advancing developmental stages although it was also increased by EGF. The presence of EGF during the preimplantation development doubled the rate of implantation of the treated group as compared with controls

The clinical analysis of poor ovarian response in in-vitro-fertilization embryo-transfer among Chinese couples

Purpose To explore the prevalence, predictor of clinical pregnancy and possible aetiology of poor ovarian response (POR) in in vitro fertilization-embryo transfer (IVF-ET) in Chinese. Methods A total of 4,600 retrieval oocyte cycles were finished between July 1, 2004 and April 30, 2006. Poor ovarian responses were observed in 426 patients of 472 cycles undergoing IVF, which were selected on the same retrieve oocyte day as the control group. The outcome of IVF-ET and the common markers of ovarian reserve were compared. Results The patients had previous ovarian surgery in 64 cycles of 472 poor ovarian response cycles. The group with poor ovarian response has significant differences in comparison with the control group in age (36.6 +/- 4.2 vs 33.3 +/- 4.04), ovarian surgeries (13.6 vs 2.8%), dose of gonadotrophin (58.5 +/- 15.8 vs 40.6 +/- 17.0), fertilization rate (71.5 vs 86%) and pregnancy rate (14.8 vs 36.7%). In the group with poor ovarian responses, clinical pregnancy rate declined significantly in women aged > 40 years than in those aged >40 years (2.8 vs 18.5%, P<0.001). The age, basal serum follicle stimulating hormone (FSH), basal serum luteinizing hormone (LH), basal oestradiol (E2) concentrations, FSH to LH ratio and the antral follicle count (AFC) are the common markers of ovarian reserve in our center. We found that there were significant differences in age, basal FSH, FSH-to-LH ratio and the antral follicle count. But no statistical significant differences were observed in basal oestradiol concentration and basal serum LH when comparing the two groups. Binary logistic regression analysis was used to study the relation among age, FSH, LH, E2, AFC and clinical pregnancy, and the age (odds ratio, 0.863; 95% confidence interval, 0.805-0.925; p = 0.000) was the only variable selected. Conclusions Our data show that the prevalence of poor ovarian response in Chinese is 11.9%. Previous ovarian surgery is associated with poor ovarian responses. The pregnancy rate of women with poor ovarian response is low in IVF-ET, especially the decline in clinical pregnancy rate of women aged > 40 years became accelerated. Correct identification of those who are at risk for POR prior to stimulation is helpful in tailoring the best stimulation protocol to individual patients. Chronological age significantly improved the prediction of clinical pregnancy of poor ovarian responders.Genetics & HeredityObstetrics & GynecologyReproductive BiologySCI(E)PubMed10ARTICLE117-222