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본 연구는 체외성숙된 돼지난포란을 액상정액으로 수정시 수정시간과 배양배지가 난포란의 발달에 미치는 영향을 조사하기 위하여 실시하였다. 정자농후정액 (30∼60 ml)을 채취하여 실온에서 2시간 정도 서서히 냉각시킨 후, 정액을 15 ml 튜브에 담아 800×g로 10분간 원심분리하였다. 상층액은 버리고 하부의 정자는 5 ml LEN 희석액으로 1×10/sup 9/ 전자/ml가 되도록 재희석하였다. 희석된 정액은 4℃ 냉장고에 보존하였다. 미성숙 난모세포의 성숙에 사용된 배지는 26.19 mM sodium bicarbonate, 0.9 mM sodium pyruvate, 10 ㎍/ml insulin, 2 ㎍/ml vitamin B/sub 12/, 25 mM HEPES, 10 ㎍/ml bovine apotransferrin, 150 μM cysteamine, 10 IU/ml PMSG, 10 IU/ml PMSG, 10 IU/ml EGF, 0.4% BSA, 75 ㎍/ml sodium penicillin G, 50 ㎍/ml streptomycin sulfate그리고 10% pFF를 첨가한 TCM-199 배지였다. 22시간 성숙 배양한 후 난모세포는 cysteamine과 hormone들을 배제한 후 38.5℃, 5% CO₂ incubator에서 22시간 더 성숙시켰다. 성숙된 난모세포는 채취 후 2일간 4℃에 보존된 액상정액으로 수정되었다. 난모세포는 500 μl mTBM 수정 배지에서 1×10/sup 6/ 정자/ml의 농도로 1, 3, 6 그리고 9시간 동안 수정시켰다. 그 후 난모세포는 500 μl NCSU-23, Hopes buffered NCSU-23, PZM-3 그리고 PZM-4 배양배지에 옮겨서 6, 48 그리고 144시간을 더 배양하였다. 정자침투율, 웅성전핵형성율 그리고 난모세포의 난할율은 6 및 9시간 수정시간에서 1 및 3시간 수정시간 보다 높았다. 6시간 수정시 배반포형성율 (33.6%)은 1, 3 그리고 9시간 수정시 배반포형성율 (11.4, 23.0 그리고 29.6%) 보다 높았다. 배반포의 평균세포수는 6, 9, 3 그리고 1시간 수정시 각각 32.9, 27.6, 26.3 그리고 24.4개 였다. 분할된 난모세포의 배반포형성율 그리고 배반포의 평균세포수는 NCSU-23, PZM-3 그리고 PZM-4 배양배지보다 HEPES buffered NCSU-23 배양배지가 우수하였다. 결론적으로 4℃ 보존 돼지액상정액은 체외성숙된 돼지 난모세포의 체외수정에 사용될 수 있음이 입증되었다. 또한 체외성숙된 돼지 난모세포는 500 μl mTBM 수정배지에서 1×10/sup 6/ 정자/ml로 6시간 공배양시키는 것이 바람직하며, HEPES buffered NCSU-23 배양배지에서 배양하는 것이 좋다는 결과를 얻었다.
This study was to investigate the effects of fertilization time and culture medium of pig oocytes matured in-vitro by liquid boar sperm. The sperm rich fraction (30∼60 ml) was slowly cooled to room temperature (20∼23℃) by 2 h after collection. Semen was transferred into 15 ml tubes, centrifuged at room temperature for 10 min 800 × g, and the supernatant solution was poured off. The concentrated sperm was resuspended with 5 ml of the LEN diluent to provide 1.0×10/sup 9/ sperm/ml at room temperature. The resuspended semen was cooled in a refrigerator to 4℃. The medium used for oocyte maturation was TCM-199 supplemented with 26.19 mM sodium bicarbonate, 0.9 mM sodium pyruvate, 10 ㎍/ml insulin, 2 ㎍/ml vitamin B/sub 12/, 25 mM HEPES, 10 ㎍/ml bovine apotransferrin, 150 μM cysteamine, 10 IU/ml PMSG, 10 IU/ml hCG, 10 ng/ml EGF, 0.4% BSA, 75 ㎍/ml sodium penicillin G, 50 ㎍/ml streptomycin sulfate and 10% pFF. After about 22 h of culture, oocytes were cultured without cysteamine and hormones for 22 h at 38.5℃, 5% CO₂ in air. Oocytes were inseminated with liquid boar sperm stored at 4℃ for 2 days after collection. Oocytes were coincubated for 1, 3, 6 and 9 h in 500 ㎕ mTBM fertilization media with 1.0×10/sup 6/ sperm/ml concentration, respectively. Thereafter, oocytes were transferred into 500 ㎕ NCSU-23, HEPES buffered NCSU-23, PZM-3 and PZM-4 culture media, respectively, for further culture of 6, 48 and 144 h. The rates of sperm penetration and male pronuclear formation were higher in the fertilization times for 6 and 9 h than in those for 1 and 3 h. The rates of cleaved oocytes were higher in the fertilization times for 6 and 9 h (85.0 and 84.6%) than in those for 1 and 3 h (61.1 and 76.8%). The percentage of blastocyst formation from the cleaved oocytes was highest in the fertilization time for 6 h (33.6%) than in that for 1, 3 and 9 h (11.4, 23.0 and 29.6%). Mean cell numbers per blastocyst were 32.9, 27.6, 26.3 and 24.4 in the fertilization times for 6, 9, 3 and 1 h, respectively. The rate of blastocyst from the cleaved oocytes and the number of cells per blastocyst were higher in HEPES buffered NCSU-23 culture medium than in NCSU-23, PZM-3 and PZM-4 culture media. In conclusion, we found out that liquid boar sperm stored at 4℃ could be used for in-vitro fertilization of pig oocytes matured in-vitro. Also, we recommend the coincubation time of 6 h in 500 ㎕ TBM fertilization medium with 1×10/sup 6/ sperm/ml concentration and the HEPES buffered NCSU-23 culture medium for in-vitro fertilization of pig oocytes matured in-vitro.
