Oral repletion of iron induces free radical mediated alterations in the gastrointestinal tract of rat

Free radical mediated effects on the gastrointestinal (GI) tract were studi ed by supplementing 8 mg of iron orally for 15 days to groups of both contr ol (C+) and iron deficient (D+) rats. They were compared with their respect ive unsupplemented groups C and D. Incorporation of H-3-thymidine into the isolated mucosal cells, as a measure of cell turn over, was lowered signifi cantly in both the D+ and C+ groups compared to their respective controls D and C. It was observed that a single dose of 8 mg of iron given orally to control rats could cause apoptosis of GI tract mucosal cells as shown by th e ladder pattern of DNA on electrophoresis. Continuous administration of th e same dose of iron for a period of 15 days resulted in necrosis of the GI tract absorptive surface in D+ and C+ rats. In addition to this, a reductio n of microvillus height in C+ and complete erosion of the same in D+ were o bserved by the transmission electron microscopy. EPR spectroscopy identifie d production of hydroxyl and methoxyl radicals in both the luminal and muco sal contents in the GI tract of rats. These results suggest that when iron is orally administered, free radicals are formed at the site of absorption causing damage to the GI tract mucosa.