일반적인 체외성숙 과정에서 난구세포-난자 복합체 (COCs)는 난포 내 환경으로부터 격리됨으로써 성숙간 난포벽 체세포들과 COCs 간의 내분비 상호작용을 소실하게 된다. 상실된 난포 내 환경을 복원시키기 위하여 본 연구자는 IVM 동안 난구세포 유래 체세포 (CSC)를 공동배양 하였다. CSC는 각 농도에 맞게 DMEM 배지에서 48시간동안 배양되었고, 그 후 IVM 4시간전 TCM199 배지로 교체되었다. 3-6mm 크기의 난포에서 채취된 COCs는 10 IU/mL의 호르몬이 포함된 TCM199 배지에서 22시간 성숙 후 호르몬이 없는 배지에서 22시간 동안 추가적으로 배양되었다. 성숙 후 난자의 세포질 성숙도를 평가한 결과 2.5×104군에서 세포질 내 유의적으로 높은 GSH 농도를 보였으며, 피층과립 분포 또한 다른 군에 비하여 유의적으로 높게 관찰되었다. 체외 수정 후 수정률 평가에서 수정 효율이 2.5×104군(44.90%) 과 5.0×104군(46.46%)에서 대조군(32.08%)에 비하여 유의적으로 증가되었다. 성숙 후 COC에서 mRNA 발현을 분석한 결과 2.5×104군에서 PCNA, COX-2, Has2, Ptx3, 그리고 Nrf2가 유의적으로 높게 발현되었다. COC 성숙간 각 0시간, 11시간, 22시간, 33시간, 44시간별 BMP15과 GDF9의 mRNA 발현패턴을 분석한 결과 2.5×104와 5.0×104군에서 33시간과 44시간에서 유의적 발현변화를 가져왔다. 체외수정과 단위발생을 통한 성숙란의 발달능 평가 결과를 실시한 결과 체외 수정 후 2.5×104군 (60.00%, 35.68%, 127.25)에서 대조군 (43.15%, 21.05%, 89.28)에 비해 유의적으로 높은 분할율, 배판포 형성률, 세포수를 보였고, 단위발생 배아에서는 2.5×104군(49.15%)과 5.0×104군 (48.21%)에서 대조군(28.33%)에 비해 유의적으로 높은 배판포 형성률을 보였다. 결론적으로 이 결과는 체외성숙 동안 2.5 × 104 CSC와 공동배양 할 때, 난자의 성숙간 GDF9과 BMP15의 발현조절을 통해 세포질 내 GSH와 피층과립을 증가시킴으로써 체외수정 및 단위발생 배아의 발달능을 상보적으로 향상시킴을
In the process of in vitro maturation (IVM), cumulus-oocyte complexes (COCs) separate from the follicular microenviroment, leading to the loss of endocrine interactions between follicular mural somatic cells and COCs. To restore the microenviroment, a co-culture system was established using cumulus-derived somatic cells (CSCs) for IVM. The CSCs were cultured in Dulbecco’s modi?ed Eagle''s medium (DMEM) for 48 h with varying numbers of CSCs (0, 2.5-, 5.0-, and 10.0×104), then cultured in TCM 199 for 4 h before adding the oocytes. COCs from 3- to 6-mm follicles were matured in 500 μL TCM 199 with eCG and hCG for 22 h and then cultured in M199 without hormones for 22 h. After IVM, the group with 2.5×104 CSC showed a significant increase in intracellular GSH levels compared to the control group. Intracellular cortical granule (CG) distribution increased dramatically in the 2.5×104 CSC group compared to the other co-culture groups (13.71, 29.23, 18.34, and 19.52, respectively). In the evaluation of sperm penetration, efficient fertilization was increased in the groups with 2.5- and 5.0 ×104 CSC compared to controls (44.90 and 46.46 vs. 32.08, respectively). The mRNA expression pattern analysis in matured COCs showed significant upregulation of PCNA, COX-2, Has2, Ptx3, and Nrf2 in the 2.5×104 CSC group compared to controls. During COC maturation at 0, 11, 22, 33, and 44 h, the 2.5- and 5.0×104 CSC groups showed significantly altered mRNA expression of BMP15 and GDF9. The developmental competence of the matured oocytes in all groups was evaluated after in vitro fertilization (IVF) and parthenogenetic activation (PA). After IVF, the 2.5 CSC group showed significantly higher cleavage, blastocyst formation rate, and total cell numbers compared to controls (60.00%, 35.68%, and 127.25 vs. 43.15%, 21.05%, and 89.28, respectively). After PA, the 2.5- and 5.0×104 CSC groups had significantly higher blastocyst formation rate than controls (49.15 and 48.21% vs. 28.33, respectively). In conclusion, this results suggest that the presence of a population of 2.5×104 CSCs during IVM synergistically improved the developmental potential of IVF- and PA-derived porcine embryos by increasing the intracellular GSH level and CG distribution via regulation of BMP15 and GDF9 gene expression during oocyte maturation.
Ⅰ. INTRODUCTION 1Ⅱ. MATERIALS AND METHODS 41. Chemicals 42. Oocyte collection and in vitro maturation (IVM) 43. Isolation of cumulus-derived somatic cells4. Fluorescent staining for assessment of nuclear status 65. Measurement of intracellular ROS and GSH levels 66. Parthenogenetic activation (PA) and in vitro culture of porcine embryos 77. Process of in vitro fertilization (IVF) 78. Assessment of fertilization parameters 89. Embryo evaluation and total cell counts 810. Measurement of intracellular cortical granules 911. Real-time PCR and gene expression analysis 912. Statistical analysis 12Ⅲ. RESULTS 131. Effects of co-culture with CSCs during porcine oocyte IVM 132. Effects of co-culture with CSCs on intracellular GSH and ROS levels in porcine oocytes matured in vitro 153. Effects of co-culture with CSCs on matured oocyte cortical granules during IVM 174. Effects of co-culture with CSCs after IVM on the development of PA and IVF embryos5. Effects of co-culture with CSCs during IVM on gene expression in maturing COCs, matured COCs, and PA- and IVF-derived blastocysts 24Ⅳ. DISCUSSION 29Ⅴ. REFERENCES 35SUMMARY IN KOREAN 43