American Society for Reproductive Medicine (ASRM) (Washington, DC）

The effect of cumulus co-culture in ICSI

• Objective

  We have had many successful births by ICSI, which is adopted to patients that have severe male factor or have experienced failure of fertilization by IVF. However, there is a difference in growth speed or grade of embryos when comparing ICSI cycles and IVF cycles. We believe that such a difference is caused by the peculiar fertilization process of ICSI. Another reason is that there are cumulus cells which help fertilization and development in IVF cycles. However, there are none in ICSI cycles. Therefore, we reviewed whether or not the fertilization rate and development rose when doing cumulus co-culture in ICSI cycles.

• Design

  We dealt with the ICSI cycles that have equal to or more than four metaphase II oocytes. We divided them into two groups: the co-culture group and the control group. Materials and Methods: We dealt with 12 cycles (102 oocytes) that have equal to or more than four metaphase II oocytes. Oocytes were prepared for ICSI by standard protocols and denuded by exposure to a hyaluronidase solution. However, in the co-culture group, we removed cumulus cells by cutting before exposing the oocytes to the hyaluronidase solution. After the ICSI procedure, we then re-introduced the removed cumulus cells to the culture medium. We did co-culture for 25 hours. In the control group, we did not do co-culture. We observed the rates of fertilization (18 hours after ICSI), first cleavage (25 hours after ICSI), grade of embryo development (66 hours after ICSI) and blastocyst formation (114 hours after ICSI) and compared the two groups.

• Materials and Methods

  A total of 137 women seeking treatment by ICSI. The women were divided into two study groups: 84 cycles using Laser-assisted ICSI and 119 cycles using Non-laser ICSI. A compared fertilization rate, survival rate, blastocyst formation rate, pregnancy rate, implantation rate, multiple pregnancy rate, and miscarriage rate of both group.

• Results

  There was not a significant difference in the rate of fertilization between the co-culture group and the control group (67.9% vs. 54.3%). However, the rate of first cleavage (35.3% vs. 0.0%, p<0.01) and blastocyst formation (57.1% vs. 26.1%, p<0.05) were significantly higher in the co-culture group compared with the control group. Also, the rate of embryos that stopped development in 66 hours after ICSI was significantly higher in the control group (13.5% vs. 40.0%, p<0.05).

• Conclusions

  Thus, we conclude that cumulus co-culture in ICSI cycles was beneficial for embryo development.