Time-lapse imaging of necrosis.

The processes of dying are as tightly regulated as those of growth and proliferation. Recent work into the molecular pathways that regulate and execute cell death have uncovered a plethora of signalling cascades that lead to distinct modes of cell death, including "apoptosis," "necrosis," "autophagic cell death," and "mitotic catastrophe." Given that cells can readily switch from one form of death to another, it is vital to carefully monitor the form of death under investigation. Particularly, end-point techniques are intrinsically unsuitable for assessing apoptosis versus necrosis, as they cannot reconstruct the sequence of events that have led to cell death. Since apoptotic cells frequently undergo secondary necrosis under in vitro culture conditions, novel methods relying on high-throughput time-lapse fluorescence video microscopy have been developed. Here we describe the use of this technique to reliably distinguish necrosis from apoptosis and secondary necrosis.