The effect of gases in the intraperitoneal space on cytokine response and bacterial translocation in a rat model

Background: The aim of this study was to examine cytokine response and bacterial translocation after exposure of the intraperitoneal space to carbon dioxide (CO2), helium (He), and air (Air) in a rat model. Methods: For this study, 120 Sprague-Dawley rats underwent anesthesia only (Control), 10 mmHg pneumoperitoneum (PP), or abdominal wall lift (AWL). The rats were divided into five groups according to experimental procedure: Control, PP-CO2, AWL-CO2, AWL-He, and AWL-Air. At 0, 3, 6, and 24 h after the procedures, the levels of interleukin 1b (IL-1b) and interleukin 6 (IL-6) in both plasma and peritoneal lavage fluid (PLF) were measured, and the translocation of bacteria to the mesenteric lymph nodes was evaluated. Results: The plasma IL-1b and IL-6 levels in the PP-CO2, AWL-CO2, and AWL-He groups were significantly lower than those in AWL-Air group at 6 h (p <0.05). The PLF IL-1b (at 3, 6, and 24 h) and IL-6 (at 6 h) levels in the AWL-CO2 group were significantly lower than those in the AWL-Air group (p <0.05). There were no significant differences in IL-1b and IL-6 responses among the PP-CO2, AWL-CO2, and AWL-He groups. The AWL-CO2 and PP-CO2 groups had lower incidences of bacterial translocation than did the AWL-Air group (p <0.05). Conclusions: The results from this study suggest that the gas in the intraperitoneal space, but not the increased intra-abdominal pressure, causes the alterations in host cytokine response and bacterial translocation. Carbon dioxide may play a primary role in the reduced immune response associated with laparoscopic surgery.