Morphological criteria to distinguish cell death induced by apoptotic and necrotic treatments.

We present a comparative study of apoptotic and necrotic morphology (light and scanning electron microscopy), induced by well known experimental conditions (photodynamic treatments, etoposide, hydrogen peroxide, freezing-thawing and serum deprivation) on cell cultures. Our results indicate that morphological criteria (apoptotic cell rounding and shrinkage, and appearance of membrane bubbles in early necrosis) allow to distinguish these cell death mechanisms, and also show that, independently of the damaging agents, the necrotic process occurs in a characteristic sequence (coalescence of membrane bubbles in a single big one that detaches from cells remaining on the substrate).