Microinjection of antisense c-mos oligonucleotides prevents the progression of meiosis in human and hamster oocytes.

Objective: To investigate the role of c-mos proto-oncogene in the progression of meiosis in human and hamster oocytes.

Design: Controlled basic research study.

Setting: Assisted reproduction units at medical institutions.

Patient(s): Consenting in vitro fertilization patients.

Intervention(s): None.

Main Outcome Measure(s): Maturation to metaphase II (MII) 24 hours following microinjection of prophase I (PI) hamster oocytes with antisense (AS) and sense (S) c-mos oligonucleotides. Control oocytes (C) injected with medium or left uninjected (UI). In human oocytes, maturation to metaphase II was also measured except culture was extended to 48 hours and the sense group was omitted.

Result(s): The percentage of hamster oocytes reaching metaphase II after 24 hours was as follows: 1.5% (1 of 65) for the antisense group; 63.1% (41 of 65) in the sense group; 66.1% (41 of 62) in the control group; and 69.3% (52 of 75) in the uninjected group. The percentage of human oocytes at metaphase II was 33.3% (4 of 12) in the antisense group, 83.3% (10 of 12) in the control group, and 82.8% (24 of 29) in the uninjected group.

Conclusion(s): These results demonstrate that injection of c-mos antisense oligonucleotide significantly inhibits the progression of meiosis in hamster (P=.0001) and human (P=.05) oocytes. Thus, c-mos proto-oncogene may be one of the critical regulators of meiosis in these two species.