Expression of angiogenic factors in cryopreserved mouse ovaries after heterotopic autotransplantation

Abstract

ObjectiveRevascularization is critical for successful ovarian tissue transplantation. Vascular endothelial growth factor (VEGF) andangiopoietin-2 (angpt-2) are the principal mediators of neovascularization. This study was designed to assess VEGF andangpt-2 levels in cryopreserved ovarian tissue after heterotopic autotransplantation. Methods Ovarian tissues harvested from ICR mice at 5 to 6 weeks of age were stratified as follows: no cryopreservation (controls,group I); vitrification in VFS-40 (vitrification, group II); and gradual freezing in dimethyl sulfoxide (slow-freezing, group III). Frozen specimens were thawed at room temperature, assaying VEGF and angpt-2 levels 1 week after cryopreservation and 2weeks after autotransplantation. Results VEGF and angpt-2 protein levels were significantly lower in cryopreserved ovaries of groups II and III than in controls (group I,P<0.05), whereas groups II and III did not differ significantly in this regard. After autotransplantation of cryopreserved ovariantissue, VEGF and angpt-2 protein levels did not differ significantly by technique but tended to be lower than correspondinglevels in controls. Conclusion Expression of angiogenic factors in ovarian tissue is thought to vary by method of cryopreservation. Our findings indicatethat levels of angiogenic factors expressed in cryopreserved ovarian tissue after autotransplantation do not differ appreciablyfrom control levels, regardless of cryopreservation technique.