روش بهينه انجماد شيشه اي بلاستوسيست هاي گاوي با استفاده از كرايوتيپ دست ساز

Optimized Method for Bovine Blastocyst Vitrification Using a Simple Hand-Made Cryotip

Objective: This study introdu ced a simple method for bovine blastocyst vitrification. Materials and Methods: Bovine blastocysts were produced in vitro by means of a whole co-culture system with vera cells . The blastocysts were randoml y divided 1:3 into either vitrification (100 blastocysts ) or control (43 blastocysts ) groups. For vitrification,expanded - blastocysts were incubated first in equilibration medium for 8 minutes and then in the vitrification solution for 1 minute . The blastocysts were then loaded in the tip of a handmad e cryotip for immediate - deep freezing in liquid nitrogen . Frozen embry os were then warmed by directly immersing the tips in sequential warming solutions . warmed embryo s were cultured for a further period of 48 hours when the ratios of re-expan sion, hatching and degeneration were compared with the control group. Results : After warming , in the vitrified and control groups the ratios of re-expansi on were 78.5% ± 0.067 and 81.6% ± 0.072, the ratios of hatching were 43.7% ± 0.083 and 49.8% ± 0.089 and the ratios of degeneration were 36% ± 0.082 and 22.3% ± 0.087, respectively, which were not significantly different between the two groups . Conclusion: Post - warming survival of the vitrified and non - vitrified embry os were not significantly different, handm ade cryotips can be used as an efficient and feasible device for bovine blastocysts vitr ification