Effect of sodium alginate on mouse ovary vitrification

The survival rate of vitrified-thawed ovarian tissues after autotransplantation still needs to be improved. Therefore finding an ideal cryoprectant to reduce the damage to ovaries that caused by vitrification will pave the way for application of ovary cryopreservation on clinics. Experiments were conducted to investigate the effect of sodium alginate in cryoprotectant solution on mouse ovaries during the vitrification process. The ovaries obtained from 6-weeks old CD1 were assigned into six groups from A to F. Group A without treatment was used as the normal control. Group B cryopreserved with the basic cryoprotectant solution containing 15% each Me₂SO and EG was used as the experimental control. Groups C, D, E, and F cryopreserved with the basic cryoprotectant solution supplemented with 0.05%, 0.10%, 0.15%, and 0.20% of sodium alginate, respectively, were assigned for the experimental groups. The in vitro analyses showed that the developmental capability of the oocytes isolated from vitrified-thawed ovaries significantly increased with increasing concentration of sodium alginate in the cryoprotectant solution (groups: A = 70 ± 2; B = 43 ± 2; C = 48 ± 3; D = 53 ± 3; E = 60 ± 3; B < C < D < A, P < 0.05), and reached its highest level in group E with 0.15% of sodium alginate (P < 0.05). The lowest developmental capability of all groups was group F (41 ± 1%)(P < 0.05) with 0.20% of sodium alginate. The similar results were obtained by the autotransplantation in vivo. These finding demonstrated that sodium alginate can significantly reduce the damage to ovaries by vitrification.