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영어

Successful cryopreservation of bovine oocytes is a very important technology for research and commercial applications. However, the survival and development rate of vitrified- thawed oocytes is lower then non-vitrified oocytes. This study was confirmed the effect of cryoprotectant solutions treated with Hydroxypropyl cellulose (HPC) supplementation for oocyte vitrification in bovine. For vitrification, bovine MII oocytes were pretreated with EG10 (added 0, 10, 50 and 100 μg/mL HPC) for 5 min, exposed to EG30 (added 0, 10, 50 and 100 μg/mL HPC) for 30 sec, and then directly plunged into LN2. Thawing was taken by 4-step procedures [1 M sucrose and 10% FBS added D-PBS (SFD) → 0.5 M SFD → 0.25 M SFD → 0.125 M SFD ] for 1 min, respectively. After thawing, cumulus cells were partially removed by treatment with 0.05% hyaluronidaseand mechanical pipetting. Oocytes were washed with TL-HEPES, incubated in a droplet of previous cultured IVM medium for 1 h to recover. As shown results, in vitro survival rate of bovine vitrified-thawed MII oocyte was significantly higher in 50 (85.5%) and 100 μg/mL (80.2%) groups than 0 (71.2%) and 10 μg/mL (71.3%) groups. After in vitro fertilization, the cleavage rate was no significantly different between treatment groups. Therefore, these results were shown HPC treatment have a positive effect on the survival of vitrified-thawed bovine oocytes.