Changes of immunocytes and macrophages in gut-liver-lung axis in rats with sever acute pancreatitis

Objective To observe the changes of immunocytes and macrophages in gut, liver and lung in rats with severe acute pancreatitis (SAP) and the effect of glutamine on these changes. Methods Fifty-four SD rats were randomly divided into 3 groups; sham operation group(SO, n=18), SAP group (n=18), and GLN group (SAP rats treated with Glutamine, n=18). The SAP model was induced by injection of 5% sterile sodium taurocholate solution into the bili-pancreatic duct. Isocaloric and isonitrogenous amino acid solution was infused continuously to the rats by a mini-pump via a central intravenous line. The rats in GLN group received 3% glutamine dipeptide solution (equivalent to 2% glutamine) with a dosage of 0. 5 g ·kg-1·d-1. The rats were sacrificed at 24 h, 48 h and 72 h after operation. Endotoxin in portal vein, and CD3+, CD4+, CD8+ lymphocytes in intestinal mucosa and macrophages in liver and lung were determined by immunohistochemistry methods. Results The endotoxin concentration was increased significantly in SAP group in a time-dependent manner (P 0. 05. vs SO group), while glutamine decreased the endotoxin significantly (P0. 05). The number of CD3+, CD4+, CD8+ lymphocytes was decreased in SAP group(P0. 05, vs SO group) and increased in GLN group(P0. 05, vs SAP group). The macrophages in the liver and lungs were accumulated in SAP group, especially at 24 h after the operation, but disappeared in glutamine treated rats. Conclusions The immunocytes dysfunction in the gut and the over-activation of macrophages in the liver and lungs are implicated in the development of SIRS in the setting of SAP. Glutamine protected the intestinal immune barrier, prevented endotoxin translocation and inhibited excessive activation of macrophages.