Static magnetic field improves post vitrification quality of mouse GV oocytes

Introduction and Objectives: Preservation of women fertility is a critical issue in assisted reproductive technology (ART). Nowadays, vitrification become an applicable method for banking of oocytes. Ice crystal formation is one of the main issues during vitrification and warming procedure which lead to cell cryo-injuries. Different studies showed that static magnetic field (SMF) could improve vitrification in owing its cryoprotective properties. The aim of this study was to evaluate the effect of SMF on oocyte maturation.Material and Methods: GV oocytes from 6-8 weeks NMRI mice were used in this study. Oocytes were vitrified by 2 steps vitrification, briefly, GVs were exposed to equilibration medium (7.5% EG plus 7.5% DMSO (v/v)) for 5 minutes and then washed in vitrification solution (15% DMSO, 15% EG, 0.5M/L sucrose) for 1 minute. Afterward, they were quickly loaded on cryotop and plunged into liquid nitrogen. For warming, the samples were exposed to 1, 0.5 and 0.25M/L sucrose of warming solutions for 1, 3 and 3 minutes respectively. Neodymium ring magnets with (20±2mT, 40±2mT, 60±5mT and 80±5mT) also were applied along with vitrification process in other groups. Trypan blue and JC 1 staining were used to assess viability and mitochondrial membrane potential.Results: However, the mitochondrial activity decreased significantly in vitrified and vitrified plus 80mT groups (p<0.05) in comparison to control group, but it increased in SMFs 20mT, 40mT and 60mT. There were no significant differences in viability rates between experimental groups. Although the maturation rate was not meaningfully altered in vitrified (71.6±1.7), vitrified plus 20mT (80.8±5.4), 40mT (71.4±2.22) and 60mT (78.2±5.5) groups comparing to control group (72.6±3.1), but it reduced significantly (p<0.05) in 80mT (56.3±2.4) as compared to vitrified plus 20mT group.Conclusion: It seems that vitrification along with SMF could improve vitrified oocytes quality.

کلیدواژه ها:

In-vitro maturation ، Mitochondrial membrane potential ، Static magnetic field ، Vitrification