Korean J Fertil Steril.  2002 Sep;29(3):167-178.

The Study on Apoptosis and Expression of Fas, Fas-ligand, Bax, and Bcl-2 in Human Fragmented Embryos

• Kim JS
• Kim MS
• Yang HW
• Yu CH
• Yoon YD
• Bae IH
• Jung BJ
• Song HJ

Abstract

OBJECTIVE
The present study was performed to investigate whether apoptosis occur in human embryos by annexin staining and detect the expression of Fas, Fas-ligand (FasL), Bax, and Bcl-2 in human fragmented embryos derived from IVF-ET by immunofluorescence and Western blot analysis.
MATERIALS AND METHODS
Using annexin staining, immunofluorescence and Western blot analysis on normal and fragmented embryos, we were able to detect apoptotsis and apoptotic gene products in fragmented embryos.
RESULTS
Phosphatidylserine (PS) translocation, the marker for apoptosis, were detected frequently in fragmented embryos. Bcl-2 and Bax protein were detected in both fragmented and non-fragmented embryos. When fragmented embryos compared to normal embryos, immunofluorescent intensity of Bcl-2 tended to be lower in fragmented embryos. Bax gene expression increased in the fragmented embryos compared to the normal embryos. This result supports a model in which the molar ratio of Bcl-2 to Bax determines whether apoptosis induced or inhibited in human embryo. Fas was highly expressed in human preimplantation embryos but not FasL. It suggests that embryo may undergo apoptosis by binding with FasL produced by follicular or immune cells.
CONCLUSION
The over expression of Bax and Fas will trigger apoptosis to lead embryo fragmentation and change embryo to be nonviable.

Keyword

Apoptosis; Fas; Fas-ligand (FasL); Bax; Bcl-2; Human fragmented embryos

MeSH Terms

Apoptosis*
bcl-2-Associated X Protein
Blastocyst
Blotting, Western
Embryonic Structures*
Fluorescent Antibody Technique
Gene Expression
Humans*
Molar
bcl-2-Associated X Protein