ORIGINAL ARTICLE: Mifepristone as an Anti‐Implantation Contraceptive Drug: Roles in Regulation of Uterine Natural Killer Cells during Implantation Phase

Abstract

PROBLEM: To investigate the immunological mechanism of low-dose mifepristone acting as a contraceptive at the level of the endometrium. METHOD OF STUDY: Endometrial explants were cultured in vitro with or without mifepristone treatment for 24 hr. Some tissues were fixed and immunostained for CD56, while other tissues were dissociated and cells analysed by three colour flow cytometry for CD3, CD56 and CD16. RESULTS AND CONCLUSION: Results showed a significant increase in the number of CD56(+) natural killer (NK) cells and the percentages of CD3(-) CD56(+) CD16(-) NK cell subset in the tissue treated with mifepristone, while the percentage of CD3(-) CD56(+) CD16(+) NK cell subset remained unaffected. It shows that low-dose mifepristone increases the number of CD56(+) NK cells and the percentage of CD3(-) CD56(+) CD16(-) NK subset in receptive endometrium and provides new insights into the immunological mechanism of low-dose mifepristone as an anti-implantation contraceptive drug.