Abstract
The objective of this study is to determine the developmental competence of in vitro matured bovine oocytes after intracytoplasmic sperm injection(ICSI) with frozen-thawed epididymal spermatozoa. The ovaries were obtained from slaughtered Korean native cows. Oocytes matured in vitro for 24 hrs were fertilized by ICSI with frozen-thawed epididymal spermatozoa. After ICSI, a group of oocytes was activated with 7% ethanol fur 5 min, and the other group was not activated. The oocytes were cultured in TCM-199 medium containing hormones and 10% FCS for 24~30 hrs in a incubator with 5% $CO_2$ in air at 38.5$^{\circ}C$. The percentage of oocytes reaching M II after 24 hrs and 30 hrs of incubation were significantly higher(p<0.05) after culture with TCM-199 media(80.0% and 88.3%) than M I(8.3% and 6.7%). The rate of cleavaged embryos to blastocyst obtained by ICSI treated activation oocytes was significantly higher(p<0.05) than that of nonactivation oocytes(22/46, 47.8% vs 10/39, 25.6%). The rates of embryos development to blastocyst obtained by ICSI treated sperm of flesh, epididymal and frozen-thawed epididymal were 24/45(53.3%), 15/40(37.5%), 11/43(25.6%), respectively and these values of fresh sperm injection were higher than frozen-thawed epididymal sperm. We also concluded that embryos can be produced with ICSI of in vitro matured oocytes by ICSI using frozen-thawed epididymal semen.
ICSI시 동결 융해한 부고환 정자의 이용 가능성을 알아보고자 난자의 배양시 체외성숙율과 활성화 처리를 한 난자와 동결 융해한 부고환 정자로 ICSI시 체외발생율을 조사하였으며, 결과를 요약하면 다음과 같다. 1. 난포란을 회수 후 24시간 배양하였을 때 배양 시간에 따른 GV, MI, M II로의 체외성숙율은 각각 7/60(11.7%), 5/60(8.3%), 48/60(80.0%)였고 30시간 배양 시간에 따른 GV, MI, M II로의 체외성숙율은 각각 3/60(5.0%), 4/60(6.7%), 53/60(88.3%)였고 퇴화란은 각각 2/60(3.3%)와 1/60(1.7%)였다. 2. 동결 융해한 부고환 정자를 이용하여 활성화 처리를 한 난자에 ICSI를 하였을 때 상실배와 배반포로의 체외발생율은 각각 12/46(26.1%), 22/46 (47.8%)로서 비활성화처리 난자군 5/39 (12.8%), 10/39(25.6%)에 비해 높은 체외발생율을 나타냈다. 3. 활성화 처리를 한 난자에 신선정자, 부고환 정자 및 동결 융해한 부고환 정자로 ICSI시 체외 발생율은 각각 24/45(53.3%), 15/40(37.50%), l1/43 (25.6%)로서 신선정자에 비해 동결 융해한 부고환 정자처리군은 체외발생율은 약간 낮았지만 이용 가능성이 있음을 확인하였다.