P-430 Characterization of secondary follicles from cultured cryopreserved-thawed human ovarian cortical tissue

Abstract Study question Can we obtain secondary follicles from cultured cryopreserved-thawed human cortical tissue? Summary answer We obtained a comparable percentage of after culture tissue to that reported fresh tissue. What is known already The complete in vitro maturation oocytes starting primary (present unilaminar follicles) until mature MII has been achieved previously by two different multi-step protocols. These protocols were applied ovarian adult cisgender donors. However, the efficiency these for growing cryopreserved patients not investigated. As available fertility preservation cryopreserved, it important understand potential vitro. design, size, duration Cryopreserved 4 donors was used culture. According existing protocols, either 8 days using first step medium (Telfer’s medium) M.McLaughlin 2018 (doi: 10.1093/molehr/gay002) or 7 and 21 (Xu’s Xu 2021 10.1093/humrep/deab003). Participants/materials, setting, methods Ovarian undergoing oophorectomy purposes before chemotherapy. thawed cut into small pieces. Several pieces fixed immediately (day 0), others Telfer’s Xu’s medium. After culture, follicle survival, growth morphology assessed histology immunofluorescence. Main results role chance performed quantification follicular stages (primordial, primary, atretic) observed increased independently media used. protocol resulted higher lower atretic compared protocol. further immunostained TUNEL, PCNA, COLLIV, STAR, AMH KRT19. present showed more proliferative (PCNA+) FOXL2+ granulosa cells less apoptotic (TUNEL+) stromal cells. By contrast, Moreover, expression high low Finally, both cultures KRT19 Limitations, reasons caution number limited study lacked as control. Only Telfers’ performed, hence required determine whether possible Wider implications findings Our evidence period This an achieve could be clinical applications. Trial registration NOT APPLICABLE