Int. J. Dev. Biol. 51: 157 - 160 (2007)

https://doi.org/10.1387/ijdb.062203al

Vol 51, Issue 2

Isolation of apoptotic mouse fetal oocytes by AnnexinV assay

Technical Article | Published: 1 February 2007

Anna-Maria Lobascio, Francesca-Gioia Klinger and Massimo De Felici*

Department of Public Health and Cell Biology, Section of Histology and Embryology, University of Rome "Tor Vergata", Rome, Italy.

Abstract

Expression of phosphotidylserine by fetal oocytes in culture renders significant numbers of such cells able to bind AnnexinV-coated microbeads and allows their separation from Annexin V-negative oocytes on a Magnetic Cell Separation (MACS) column in a magnetic field. The majority of oocytes >=75%) which bound Annexin V-coated microbeads were viable, as indicated by their propidium iodine (PI) negativity. However, they showed apoptotic morphologies and were found to be TUNEL-positive. On the other hand, AnnexinV-negative oocytes, besides being PI negative, appeared morphologically healthy and TUNEL negative. Moreover, AnnexinV-positive oocytes showed a marked lower ratio of Bcl-xL/Bax transcripts in comparison to AnnexinV-negative oocytes. We conclude that the present method is able to separate fetal oocytes in two distinct populations: AnnexinV-positive oocytes showing features typical of apoptotic cells and AnnexinV-negative oocytes comprising for the most part viable non-apoptotic cells. This procedure should greatly facilitate studies aimed to identify the currently poorly understood molecular pathways governing apoptosis in mammalian fetal oocytes.

Keywords

apoptosis, oocytes, annexinV, meiosis