Studies on In Vitro Fertilizability of Mouse Oocytes Pre-exposed to Dibutyryl Cyclic AMP

Dibutyryl Cyclic AMP로 처리된 생쥐난자의 수정능에 관한 연구

The present study was carried out to examine the fertilizability of the mouse oocytes pre-ex-posed to dbcAMP which is a well-known inhibitor of the oocyte maturation. The oocytes once cultured in the dbcMP-containing medium for a certain length of, time were cultivated in the dbcMp-free medium to induced the maturation, then mixed with sperms, and observed following culture for 24 hours. The fertilization rate of cocytes was judged by the index of the number of 2-cell embryo developed 24hr following insemination. The fertilization rate of the oocyte previously incubated with dbcAMP (100 g/ml) for 2, 4, 8 16 hours was 32.3, 14.5, 4.7 and 8.8%, respectively, while that of the control was 53.3% indicating that the fertilizability was decreased as a function of time exposed to dbcAMP. The pretreatment of dbcMP, however, didn't affect the process of sperm penetration to egg. In addition, there is no prominent changes in the morphological architecture of fertielized eggs which has been exposed to dbcAMP as revealed by electron microscopic observation. Consequendy, it can be concluded that the mouse cocytes once inhibited their maturation by dbcMP may retain, in some extent, the fertilizability, although most of the fertilized egg may not proceed to further development because of the failure of pronucleus formation.

dbcAMP에 의해 성숙이 억제된 생쥐난자의 수정능을 조사하기 위해 본 실험을 행하였다. dbcAMP로 일시 성숙이 억제되었던 난자를 배양액내에서 정자와 섞고 24시간 배양한 후 발생한 2세포기의 배아형성, 정자의 관입, 전액형성을 조사하여 2세포기로 배아발생이 진척된 것을 수정율의 기준으로 정하였다. dbcAMP를 처리하지 않은 난자는 약 53.3%의 수정율을 보였으며,dbcAMP가 함유되 배양액에서 배양한 후 기본 배양액에서 성숙시킨 난자들의 수정율은 dbcAMP의 처리시간에 비례하여 낮으나, 정자의 관입은 정상적으로 일어났다. 전자현미경적 관찰에 의하면 dbcAMP 처리는 난자의 미세구조에 어떠한 변화도 야기하지 않았다. 따라서 dbcAMP를 사전처리하여 성숙을 억제한 난자라할지라도 어느 정도의 수정능력을 보유하고 있다고 사료된다.