Document Type : Original Article
Experimental Embryology Department, Royan Infertility clinical and Research center, Tehran, Iran
Introduction: In this study the immature mouse oocytes (Germinal Vesicles: GV), which were arrested in metaphase (MI), were activated with DC pulses and the effect of DC pulse frequency on immature oocyte activation and their subsequent in vitro development were studied.
Material and Methods: Immature oocytes successfully passed the meiosis processes. That is, germinal vesicle stage of oocytes changed to germinal vesicle breakdown (GVB) and finally the first polar body extruded and reached metaphse II, (MII) and formation of 2-cell, 4-cell, 8-cell embryos. Immature Oocytes were separated from NMARY mice (4-6 week old) ovary in different phases. They were placed in M2 medium droplet and then activated with DC pluse (50V, 30µs).
Results: Immature oocytes (GV) began meiosis resumption and GVs changed to GVB and extruded first polarbody and some of them reached metaphase II. After 24 hours evaluation by inverted microscope was performed. Ovulated oocytes were inseminated with the capacitded epididymal sperm of the same strain of mice. One to four pulses with a duration of 30مs induced more oocyte activation (67% to 89%), maturation (68 to 77%) and embryo formation (44% to 84%). Embryo formation increased significantly with more than two DC pulses (55-88%) compared with a frequency of less than two (51%) groups.
Conclusion: This study revealed that electroactivation is helpful for in-vitro maturation, fertilization, embryo formation and development in female infertility, especially in those with irrgular secretion of follicle stimulating and luteinizing hormone (FSH, LH)