earticle

영어

Less than two layers of cumulus cells in cumulus cell-oocyte complexes (COCs) considered morphologically poor in pig. Much to our regret, COCs of more than half included in poor group. If we could take full advantage of all of these poor quality COCs, we could dramatically improve the efficiency of in vitro embryo maturation. During in vitro maturation, some maturation factors are interacted bidirectionally between oocyte and cumulus cells, also interaction occurs between COCs and other COCs. We hypothesized that poor COCs suffer a failure in complete embryo maturation due to their insufficient maturation factor secretion. Therefore, we tried whether it increases the maturity and utilization of poor COCs if we co-culture good COCs and poor COCs. We harvested 6,201 COCs, classified them into grades I～IV. We investigated maturity, glutathione levels, embryo development capacity, blastocyst quality, and cumulus gene expression levels with suitable methods. 6,201 COCs were classified grade I (N=534, 8.6%), grade II (N=1,886, 30.4%), grade III (N=3,109, 50.1%) and grade IV (N=672, 10.9%). Our results showed that oocyte maturation, glutathione levels, embryo development capacity, blastocyst quality, and cumulus gene expression levels of BCL-2 and PCNA were similar to co-cultured good quality groups, all of which were substantially higher than the poor group. Our results suggest that co-culture strategy have considerably increased the utilization of poor COCs without reducing their ability for maturity and development capacity.