EXPOSURE OF THE PERITONEAL-CAVITY TO AIR REGULATES EARLY INFLAMMATORYRESPONSES TO SURGERY IN A MURINE MODEL

Factors in circulating air may play a role in immune responses after s urgery through induction of gut-derived lipopolysaccharide (LPS) trans location across the gut. CD-1 mice were randomized to one of four trea tment groups: controls, laparoscopy with carbon dioxide inflation, lap aroscopy with air inflation and laparotomy. The peritoneal and systemi c immune response was assessed by evaluating peritoneal macrophage, bl ood monocyte and neutrophil activity. In a second study, the effect of each of the treatments on fluorescein isothiocyanate (FITC)-LPS trans location across the gut was assessed. There were significant (P < 0.05 ) increases in peritoneal tissue macrophage release of superoxide and tumour necrosis factor after laparoscopy with air and laparotomy compa red with control procedures and carbon dioxide laparoscopy. However, p eritoneal macrophage FITC-Candida albicans ingestion was significantly decreased after air laparoscopy and laparotomy compared with controls and carbon dioxide laparoscopy (P < 0.05). These findings correlated with a significant (P < 0.05) decrease in CD11b expression. Significan t translocation into the peritoneal cavity and systemic circulation oc curred after air laparoscopy and laparotomy only. Factors in circulati ng air can induce LPS translocation and subsequent stimulation of post operative immune responses. The beneficial effects of laparoscopic sur gery may be explained by the minimal air contamination of the peritone al cavity.