The effect of interleukin-6 on bacterial translocation in acute canine pancreatitis

Background. Bacterial translocation from the gut to mesenteric lymph nodes and other extraintestinal sites is an important source of infection in acut e pancreatitis. Impaired host immunity is known to promote bacterial transl ocation. Interleukin-6 (IL-6) is a multifunctional cytokine that regulates the immune response, acute phase reaction, and hematopoiesis. Methods. Twenty-four mongrel dogs (18-29 kg) were studied in four equal gro ups. In Groups I and II, acute pancreatitis was induced by direct pressure injection of 4% taurocholate and trypsin into the pancreatic duct at laparo tomy. Groups III and IV had only laparotomy. Group I and III dogs were give n IL-6 (50 mu g/kg/d, sq) daily starting 24 h after operation and Group II and IV dogs received an equal volume of saline administered at similar time . All animals had blood drawn for culture, complete blood count (CBC), plat elets, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and amylase on d 0, 1, 4, and 7. On d 7, mesenteric lymph nodes (MLN), spleen, liver, pancreas, and cecum were harvested for pathology study and for cultu res of aerobic and anaerobic bacteria. Quantitative cecal cultures of aerob ic and anaerobic bacteria were obtained. Results. All Group I and Group II dogs had severe pancreatitis. The increas e of plasma CRP in Group I was sustained throughout treatment (1.3 +/- 0.3 on d 0 vs 3.1 +/- 0.3*, 3.0 +/- 0.3*, and 2.9 +/- 0.3* on d 1,4, and 7, res pectively). Plasma CRP was increased in Group II on d I and d 4 (1.3 +/- 0. 3 mg/dL on d 0 vs 3.6 +/- 0.3'* mg/dL on d 1, and 3.1 +/- 0.3* on d 4, *p < 0.05). There were no differences in white blood cell (WBC) count, differen tial, platelets, and ESR between Groups I and II. Bacterial translocation t o MLN was lower in Group I (1/6) than in Group II (6/6) (p < 0.05). All 6 d ogs in Group II had bacterial spread to distant sites compared to 2 of 6 do gs in Group I (p = 0.066). Both MLN and other distant organ cultures were n egative in Group III and only 1 of 6 MLN cultures was positive in Group IV. Conclusions. IL-6 treatment decreases bacterial translocation to MLN and ma y be beneficial in reducing septic complications in acute pancreatitis.