NITRIC-OXIDE INDUCES APOPTOSIS IN A HUMAN COLONIC EPITHELIAL-CELL LINE, T84

CHRONIC inflammation is associated with inducible nitric oxide synthas e expression in infiltrating and resident cells (epithelia neurons) an d an exaggerated release of nitric oxide. NO can induce apoptosis in m acrophages and tumour cell lines. Te investigated whether NO induced c ell death in an epithelial (T84) cell Line via apoptosis. Culture T84 cells were exposed to a bolus of NO (40 or 80 mu M) dissolved in Hank' s balanced salt solution (HBSS) supplemented with 10% fetal calf serum (FCS). After incubation for 4 h at 37 degrees C in 5% CO2, cells were either stained for DNA fragmentation with the TdT-mediated dUTP-bioti n nick end labelling (TUNEL) method, or cytosolic DNA. fragments quant ified by a cell death detection ELISA assay. Nitric oxide induced apop tosis in a dose-dependent manner which preceded frank cell death (fail ure to exclude Trypan blue). These data suggest that epithelial cell d eath may be NO dependent and via apoptosis, in states of gut inflammat ion.