Background

1. Evaluation of in vitro fertilization rate, embryo quality and development in experimental model of PCOS induced by DHEA: in mouse modelAhmadiA.¹, Raberi A. ¹, Ghafari S. ¹, Sadrkhanlou R.¹ 1Laboratory of Embryology, Department of Basic science, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran Background A B A B Polycystic ovarian syndrome(PCOS) is a heterogeneous syndrome characterized by luteinizing hormone (LH) hypersecretion, ovarian hyperandrogenism, polycystic ovaries, hyperinsulinemia from insulin resistance and reduced fecundity. Objective The aim of this study was to evaluate the rate of in vitro fertilization, embryonic development and quality in PCOS mice Cumulus Oocyte Complex in PCOS group (A) with compact cumulus cells and have poor quality as compared to control group (B), COC with expanded cumulus cells Zygote after in vitro fertilization with 2 pro nucleus and polar bodies (A) . 2 cells embryos(B) Materials & Methods The hyperandrogenized environment of PCOS was reproduced in mice by injection of DHEA ( ). Briefly, female prepubertal (25 days old) mice of the NMRI strain were injected daily with DHEA (6 mg/100 g body weight, dissolved in 0.10 ml sesame oil) for 20 consecutive days,and recreated a mouse model that resembles some aspects of the human polycystic ovary syndrome (PCOS).Mice treated with DHEA remained in constant estrus. For oocyte collection for in vitro fertilization in mice of two control and experimental groups ovarian stimulation was inducedby administration of Pregnant Mare Serum Gonadotropin (PMSG) and hCG, then collected oocytes were fertilizedby fresh sperms.Uponin vitro fertilization, the zygotes were cultured in different groups in HTF mediumcontaining 4 mg/ml BSA. The rate of fertilization, two cell embryos, blastocysts, arrested embryos and type of them was examined in period of 120 hours. The data were later compared and statistically analyzedby 2Proportion test. (p<0.05) Control group. shows normal blastocysts in control group and almost any 2 or 4 cells embryo arrest Differentiation to expanded and hatched blastocysts PCOS group: Morphologically abnormal expanded blastocyst (abnormal cavitation) RESULTS The results obtained from this study revealed that the oocytes number per mouse in PCOS groups compared with the control group have been increased but the callected oocytes in PCOS group have poor quality . After in vitro fertilization, the fertilization rate, preimplantation embryo development, embryo quality, percentage of two cell embryos and blastosystes in experimental PCOS group have been decreased significantly compared with control group and embryo arrest rate and types of arrested embryo ( I, II and III, the embryos appeared intact or partially fragmented and/or lysed) has been increased significantly in experimental group. (p<0.05) Embryos in PCOS group. Embryos arrested at 2 and 4 cells stages. embryo arrest type I, II and III; the 2 cells embryos appeared intact or partially fragmented and/or lysed CONCLUSIONS PCOS patients undergoing ovarian stimulation for in vitro fertilization (IVF) are at higher risks of impaired oocyte developmental competence, implantation failure and pregnancyloss.Thepresent study showed that experimental PCOs decreased embryo development, embryo quality and rate of two cell embryosand Blastocysts. Key words * (p<0.05) Poly cystic ovary syndrome, in vitro fertilization, zygotes, embryo development. Blastocyst stained using toluidine blue for assessment of cell proliferation