Caspase activation during spontaneous and radiation-induced apoptosis in the murine intestine

The aim of this study was to characterize the activation of caspase-3 along the crypt/villus axis in the normal and irradiated intestine and to compar e active caspase-3 expression with existing apoptosis detection techniques. Small and large intestine were removed from mice at various time points af ter exposure to 8 Gy gamma -radiation. Positive apoptotic cells stained wit h an antibody against active caspase-3, haematoxylin and eosin (H&E) or TUN EL were scored in histological sections of small and large intestinal crypt s and villi. In the control intestine, active caspase-3 expression was rare ly observed; however, expression was markedly increased following exposure to radiation and was predominantly confined to apoptotic bodies. Measuremen t of apoptosis in intestinal crypts using active caspase-3 expression gave similar results to apoptosis detected from H&E-stained sections. In the nor mal villus, active caspase-3 expression was observed infrequently and did n ot significantly increase following; radiation, consistent with a lack of a poptotic body formation from H&E sections. 'This study indicates that caspa se-3 is activated in intestinal crypts but not in villi following gamma -ra diation. Active caspase-3 detection compared favourably with existing immun ological techniques, suggesting that it is a suitable alternative method fo r apoptosis quantification. Copyright (C) 2001 John Wiley & Sons, Ltd.