Nuclear factor-kappaB regulates inflammatory cell apoptosis and phagocytosis in rat carrageenin-sponge implant model.

In the present study we investigated whether apoptosis and phagocytosis are regulated by nuclear factor (NF)-kappaB in a model of chronic inflammation. The subcutaneous implant of lambda-carrageenin-soaked sponges elicited an inflammatory response, characterized by a time-related increase of leukocyte infiltration into the sponge and tissue formation, which was inhibited by simultaneous injection of wild-type oligodeoxynucleotide decoy to NF-kappaB. Molecular and morphological analysis performed on infiltrated cells demonstrated: 1) an inhibition of NF-kappaB/DNA binding activity; 2) an increase of polymorphonuclear leukocyte apoptosis correlated either to an increase of p53 or Bax and decrease of Bcl-2 protein expression; and 3) an increase of phagocytosis of apoptotic polymorphonuclear leukocytes by macrophages associated with an increase of transforming growth factor-beta1 and decrease of tumor necrosis factor-alpha as well as nitrite/nitrate production. Our results, showing that blockade of NF-kappaB by oligodeoxynucleotide decoy increases inflammatory cell apoptosis and phagocytosis, may contribute to lead to new insights into the mechanisms governing the inflammatory process.