Digital image analysis of cells stained with the senescence-associated β-galactosidase assay

Cellular senescence plays important roles in the aging process of complex organisms, in response to stress and in tumor suppression. Several markers can be used to identify senescent cells, of which the most widely used is the senescence-associated β-galactosidase (SABG) activity. Here we describe a procedure for digital image analysis of cells stained by the SABG staining technique at pH 6 or at pH 4. This analysis is highly reproducible and sensitive to subtle differences in staining intensities resulting from diverse cellular senescence pathways in culture.