Toxicological effects of iron on intestinal cells

The aim of the present study was to investigate whether iron, which is involved in the formation of free radicals in vitro, can initiate cellular injury in human intestinal cells. The effects of various concentrations of iron were studied in preconfluent, colonic‐cancerogenous cells, and also in postconfluent, differentiating cells. Cellular damage was assessed using cell proliferation (serial cell counting), tetrazolium dye (MTT) uptake, lactate dehydogenase (LDH) release and apoptosis studies based on caspase‐3 activities. Also the activities of the major antioxidative enzymes, superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were measured after the cells had been exposed to iron. Our results indicated that preconfluent cells were more susceptible to iron toxicity, as assessed by a significant reduction in cell proliferation and MTT uptake in a concentration‐dependent manner compared to the control. However, no evidence for MTT uptake was observed in postconfluent cells. Caspase‐3 activity, an indicator of cell apoptosis, considerably increased in preconfluent cells at high iron levels compared to the control (p