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Introduction: Because tetraploid embryo is used as a base for growth and development of transgenic cells, one of the most important stages in animal biotechnology is to produce tetraploidy by electrofused 2-cell embryo. The aim of this study was to determine the effect of fusion duration on developmental rate of tetraploid embryos.
Materials and Methods: In this experimental study some of the bovine 2-cell embryos were obtained from in vitro matured and fertilized cumulus oocyte complexes 33-35 hr post fertilization as an unexposed control group (UCG). The remaining 2-cell embryos were exposed to 0.75 kilovolt per centimeter for 80 microsecond, and were transferred to SOF1 medium. Subsequently those embryos fused at 30 and 60 minute post electrofusion were categorized as fused groups (FG30 and FG60) and separated from unfused embryos as exposed control group (ECG). The developmental rate was compared between UCG, ECG, FG30, and FG60 groups and the relation between fusion duration and cleavage and developmental rate was surveyed. Results: The cleavage rate up to 8-cell stage in FG60 was increased significantly compared to FG30 (p<0.05) while the blastocyst rate has no significant difference between the two groups. The cleavage and developmental rate in UCG was significantly higher than ECG, FG60 and FG30. Chromosomal analysis showed that 76% of embryos were true tetraploid.
Conclusion: The fused embryos in FG60 had more ability to produce embryos up to 8-cell stage than FG30. The electrical pulse can decrease the cleavage and developmental ability of embryo

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Background: Maturation of oocytes and fertilization in vitro can be considered as one of the most important steps to treat infertility. In this study maturation medium was enriched with Platelet extraction (PL) which has high concentration of growth factors. Meiosis resumption and maturation was monitored after 18 hours of maturation.

Materials and Methods: In this experimental study, oocytes at germinal vesicle stage were obtained from mature NMRI female mice. Maturation medium was &alphaMEM and the control groups had 5-10% FBS and the medium in the experimental groups was enriched by 5, 10% PL and the combination of 5% PL and 5% FBS. Meiosis resumption and maturation were observed after 18 hours.

Results: The rate of matured oocytes in the experimental group 5% PL for both COC and DO group was significantly higher than the control groups (P<0.05). The maturation rate for 5% PL was 61% for the COC group and 72% for the DO group while this rate for 5% FBS control group was 53% and 50% respectively.

Conclusion: PL had a significant effect on meiosis resumption and maturation of oocyte at germinal vesicle stage. Based on these results, PL could be used as a maturation promoting factor.