Morphology and celluar proliferation of follicles from cryopreserved human ovarian tissues

Objective To compare the morphology and proliferation of primordial and primary follicles in fresh and vitrificated human ovarian tissues.Methods Human ovarian tissues were cryopreserved by direct cover vitrification(DCV) for 2 weeks.The morphology of the primordial and primary follicles from the frozen-thawed tissues was compared with those from the fresh tissues.Both fresh and cryopreservation tissues were cultured for 48 hours before the tissues were embedded in paraffin block for immunohistochemical staining for PCNA.Results The distribution of primordial and primary follicles in the fresh ovarian tissues was not different from that in the frozen tissues.The cryopreserved tissues had less abnormal morphology in primordial follicles than in primary follicles,but no difference was found between the cryopreserved tissues and fresh tissues.Positive staining on PCNA expression in granulsa cells and oocyte of transitional follicles and primary follicles as well as stromal cells were found in fresh,fresh cultured and cryopreserved cultured ovarian tissues.The fresh tissues had less positive staining on PCNA in the follicle than in the fresh cultured and cryopresered cultured tissues. Conclusion Cryopreserved human ovarian tissues by DCV can maintain partial primordial and primary follicles.Follicles in cryopreserved ovarian tissues can initiate development in vitro culture.