ENHANCED EXPRESSION OF CYTOKINE-INDUCED NEUTROPHIL CHEMOATTRACTANT (CINC) BY BRONCHOALVEOLAR MACROPHAGES IN CERULEIN-INDUCED PANCREATITIS RATS

The role of bronchoalveolar macrophages (BAMs) in the aggravation of c erulein-induced pancreatitis was studied by measuring expression of cy tokine-induced neutrophil chemoattractant (CINC) in vitro. Pancreatiti s was induced by four intramuscular injections of cerulein (50 mu g/kg at 1-hr intervals). Pancreatitis rats were injected intraperitoneally with 30 mg/kg lipopolysaccharide (LPS) 6 hr following the first cerul ein injection as a septic challenge. Rats were divided into four group s: group I, nonpancreatitis without LPS; group II, pancreatitis withou t LPS; group III, nonpancreatitis with LPS; and group IV, pancreatitis with LPS. Hyperactivity of BAMs in response to LPS was assessed as a function of in vitro CINC production. CINC concentrations of the serum and bronchoalveolar lavage fluid in group IV were significantly highe r than those in groups I, II, and III. BAMs in group II harvested 6 hr following the first cerulein injection had significantly greater CINC production than those in group I. Northern blot analysis revealed abu ndant CINC mRNA transcripts in BAMs from groups III and IV. Additional ly, myeloperoxidase activity in the lung of group IV rats 8 and 12 hr following the first cerulein injection was significantly higher than t hat in group I, II, and III rats. Significant differences in static lu ng compliance in group IV were found compared with groups I, II, and I II. These results indicate that BAMs from rats with cerulein-induced p ancreatitis were primed and had enhanced release of CINC following LPS exposure. Enhanced expression of CINC may modulate the pathogenesis o f pancreatitis-associated lung injury complicated with sepsis.