Investigation On Vitrification Of Ovary Tissue

Objective:To invsetigate the effect of vitrification on ovarian tissue.And to find out the optimal cryoprotectant for the vitrification of ovarian tissue.Methods:Ovary tissues from 10-14 dpc ICR mice and Human ovarian biopsies from 2 patients(cut in 1×1×1-2 mm3 pieces)were exposed to:40%ethylene glycol+18% Ficoll-70+0.3M sucrose;40% propylene glycol+18% Ficoll-70+0.3M sucrose;2.62M dimethyl sulfoxide+1.31M propylene glycol+0.0075M polyethylene glycol+2.6M acetamide;1.5M propylene glycol+0.1M sucrose.The viability of follicles from mice and the general morphology of human follicles were analyzed and compared with fresh group after freezing(-205℃surface vitrification) and thawing.Results:In the mice ovary tissue vitrification experiment,there are significant differences between every two formulas(P<0.01). For formula A,its recovery rates,the first day adherent rates and the fifth day adherent rates are 55.13%,30.90% and 27.05%, standard deviation(SD) are 4.72,1.60 and 4.28,and variation coefficient (CV) are 8.56,5.18 and 15.82; for formula B,its recovery rates,the first day adherent rates and the fifth day adherent rates are 42.74%,25.05% and 18.47%,standard deviation (SD) are 3.30,5.27 and 5.02,and variation coefficient (CV) are 7.72,21.02 and 27.19; for formula C,its recovery rates,the first day adherent rates and the fifth day adherent rates are 62.79%,39.39% and 32.68%,standard deviation(SD) are 5.83,2.37 and 3.13,and variation coefficient (CV) are 9.28,6.02 and 9.59; for formula D,its recovery rates,the first day adherent rates and the fifth day adherent rates are 23.89%,13.31% and 7.87%,standard deviation(SD) are 3.90,3.67 and 2.50,and variation coefficient (CV) are 16.31,27.55 and 31.79.The effect of formula C is the best in the four.In the human ovary tissue vitrification experiment,there are significant differences between the vitrified and rewarmed group and the fresh non-treated control group(P< 0.005).The best results were observed in the group C(P< 0.005).The vitrified and rewarmed samples showed 63.41% normally follicles,compared with 89.86% in fresh non-treated control. There were no statistical different between group A,B and D(P>0.05)(30.26%,36.23% and 23.60%).Conclusion:1. -205℃surface vitrification is a good method to cryoprotect ovarian tissue.2. Cryoprotectant C is a good cryoprotectant to cryoprotect ovarian tissue.