Abstract Purpose: Melatonin promotes in-vitro embryo development in different species. This study studied the effects of melatonin on in-vitro mouse preimplantation embryo development.Materials and Methods: Two-cell embryos were obtained from oviduct of 6-8 weeks female NMRI mice 48 hours after administration of an intra-peritoneal injection of 5 IU/ml pregnant mares’ serum gonadotrophin and subsequent 5 IU/ml human chorionic gonadotrophin (ip). Embryos were cultured in T6 culture medium supplemented with different dosages of melatonin {0 (control group), 100×10-6 M, 10×10-6 M, 1×10-6 M, 100×10-9 M and 10×10-9 M (1-5 treatment groups)}. With due attention to percent of embryos in different stages, the rate of development of embryos was assessed using of invert microscope. It is also compared to control group.Results: The results showed that the rate of cleavage and development of mouse the embryos to blastocyst stage increased significantly in the development culture medium supplemented with 10 and 100 nM/mg of melatonin in comparison to control group (p<0.001).Conclusion: The results of this study demonstrate that, enriching the culture medium with melatonin, improve mouse preimplantation development.

Purpose: To determine the effects of different doses of addition of exogenous epidermal growth factor (EGF) on development of pre-implantation mouse embryo.Materials and Methods: Mouse zygotes, two cell, 8 cell any morulae were collected from superovulated NMRI mice 24, 48, 64 and 80 hrs after hCG injection, respectively. The obtained embryos were cultured on medium alone, medium with 1, 4 and 10 ng/ml of EGF and recorded daily for 96 hrs. The blastulation and hatching rates of every group were compared statistically using Chi-square Test.Results: The results showed that exogenous EGF could not help zygotes to overcome on developmental block. Also, the cleavage rate to two cell stage of treated zygotes were lower than non-treated zygotes. The hatching rates of two cell embryos treated with different doses of EGF and non-treated were almost identical. The hatching rates of eight cell and morula embryos treated with 10 ng/ml of EGF were significantly higher than other doses and control embryos.Conclusion: Exogenous EGF can improve pre-implantation embryo development after eight cell stage but it can not affect the development of the stages before eight cell.

Introduction: Determination of best culture medium for fertilization and development of NMRI mice.Material and Methods: Development of fertilized mature oocytes of NMRI mice was studied for five days in several culture media (KSOM, T6, M16, CZB, G1TM ver3 and G2TM ver3) following hormone therapy with PMSG and HCG.Results: The rate of fertilization after 24 hours was 97.4% in KSOM, 83.5% in T6, 90.5% in M16, 100% in CZB and 90.9% in G1TM ver3 and G2TM ver3. The differences between CZB and KSOM culture media in comparison to T6 and M16 and G1TM ver3 and G2TM ver3 media were statistically significant (p<0.05). Blastocyte stage was seen in 96.3% of CZB group which was the highest in comparison to other culture media (p£0.05). Blastocyte formation was 80.2% in T6, 82.1% in M16, 77.6% in KSOM and 87.5% in G1TM ver3 and G2TM ver3 culture media. The highest Hatching blastocyst rate was seen in sequential medium (G1TM ver3 and G2TM ver3) and KSOM culture medium (76.1% and 66.4%, respectively) while the lowest rate was 60.3% in M16 medium. The rate of embryo degeneration was lowest in sequential medium (G1TM ver3 and G2TM ver3) (23.9%) in comparison to other groups and the difference was statistically significant regarding T6 group (51.6%) (p<0.01)Conclusion: This study reveals that CZB, KSOM and G1TM ver3 and G2TM ver3 are the best culture media for pre implantation embryo development of NMRI mice. The difference in development of mice embryos in different culture media can be due to difference in medium supplements (aminoacids) and concentration of culture medium components.

Background and purpose: In assisted reproductive (ART) laboratory, during the experimental manipulation, oocytes and early embryos are exposed to day light or artificial light for variable periods. The purpose of this study was to assess the effect of fluorescent light exposure, with intensity almost equal to that produced by microscopes in ART laboratory, on mouse early embryo development.Materials and methods: The bicellular embryos were obtained from superovulated pregnant female NMRI mice 48 hours after HCG injection. After washing, the embryos were randomly allocated in HEPES buffered HTF medium into three experimental and one control group. Two hundred and fifteen (group B), 222 (group C) and 229 (group D) bicellular embryos were exposed to fluorescent light of 800 LX for 5, 10 and 30 minutes at 37oC, respectively. The embryos of control group (215, group A), and also other groups (B, C and D) were kept on a heat plate during the time of experiment and protected from the light by covering the dishes with aluminium foil. Expanding and hatching blastocyst rates were recorded after 72 and 96 hours of culture, respectively.Results: The results demonstrated that 61.6%, 52.5% and 65.1% of embryos in the experimental groups (group B, C, and D respectively) and 61% of embryos in the control group reached to blastocyst stage. There was no statistically significant difference between the experimental and the control groups. Also the hatching rates and degeneration rates showed no significant differences between the groups.Conclusion: The fluorescent light of 800 LX for a period of less than 30 minutes had no significant effect on mouse embryo development in vitro.