Local and systemic responses to iron-dextran injected into a granuloma pouch in the rat

Many inflammatory processes are accompanied by anemia and repeated hemorrha ges, but the local and systemic effect of the iron present in the inflamed area and the availability of this iron are not known. The experimental mode l used to mimic the above situation was the carrageenan-induced granuloma i n rats with simultaneous iron-dextran injection into the granuloma pouch. W e studied the effect of iron-dextran on leukocytes from the inflammatory ex udate and the location of iron in the granuloma tissue, We also evaluated t he systemic responses by studying several iron parameters in blood and in i ron-storage organs. The results showed a reduction in the number of leukocy tes present in the exudate and a reduction in their viability and also exte nsive damage to the granuloma tissue, essentially to macrophages, caused by local iron-induced oxidative stress. A small percentage of iron reaches th e systemic circulation, and this is eventually stored in the liver and sple en as hemosiderin, which is unlikely to have any effect on anemia. In spite of its local toxicity, the accumulation of iron in inflamed areas can be i nterpreted as a protective mechanism against systemic oxidative radical rea ctions induced by iron mobilization.