Toward a new method to in situ study of apoptosis and its relations with cell cycle

Apoptosis or programmed cell death plays a key role in many biological processes particularly in oncology. The detection of apoptotic cells is crucial for the study of the phenomenon itself and its relation with the proliferative cell cycle. A new method to detect apoptosis in situ in Feulgen stained cells was developed, based on multiparametric analysis (factorial and decisional analysis), using 15 densitometric and textural parameters measured on a SAMBA 200 cell image processor. Six reference files corresponding to G1, S, and G2 phases and to apoptotic cells derived from these cell cycle phases were constructed. The projection of these files in the factorial principal plane formed distinct clusters. Using the decisional discriminant analysis, it was possible to ascertain the state (apoptosis or proliferative) and the phase for each cell of a population. The correct classification rate of this analysis was 0.9962. Determining the cell cycle phase from which each apoptotic cell comes, we are able to study the relation between apoptosis and the proliferative cell cycle. Moreover, the detection in situ allows us to study cell-cell interactions.