The Effect Of Different Insufflation Gases During Laparoscopy On Immune Response In A Rat Model With Abdominal Infection

OBJECTIVE:Laparoscopic operation is widely applied to a variety of surgical diseases.But it is unsure whether the use of laparoscopy with carbon dioxide pneumoperitoneum in abdominal infection diseases.By observing the effect of different insufflation gases on immune response in a rat model with abdominal infection,we further research the effect of laparoscopy with carbon dioxide pneumoperitoneum on infection proliferation and bacteria translocation.STUDY DESIGN:Forty male Wistar rats were inoculated intraperito- neally with 10ml/kg of a solution containing 1×10⁸ colony-forming units(CFU)/ml of Escherichia coli and were divided into four groups as follow: control (only puncture with veress needle), CO₂ pneumoperitoneum , air pneumoperitoneum and nitrogen pneumoperitoneum. The animals with pneumoperitoneum underwent anterior abdominal puncture with a transfu- sion apparatus needle followed by peritoneal insufflation with different gases(CO₂ ,air, N₂), maintaining a 5 mmHg intracavity pressure and a speed at 0.2L/min for 0.5h. The control animals only underwent anterior abdominal puncture. The procedures were performed 12h after the injection of the bacterial solution. Blood samples and ascites were collected 24h and 48h after the surgical procedures. Blood were collected from cardiac puncture for measurements of TNF-α,IL-6 and IL—2. Ascites were collected to measure TNF-α and activity of phagocytes.Furthermore, the tissues of greater omentum, liver and parietal peritoneum were cut to observe the pathologic changes.RESULTS: (1) After 24 h, the serum level of TNF-a was statistically lower in the CO₂ pneumoperitoneum group compared to the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. There was no statistical significance among the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. After 48 h, the serum level of TNF-a was lower in the CO₂ pneumoperitoneum group compared to nitrogen pneumoperitoneum group. However, there was no statistical significance among CO₂ pneumoperitoneum group, the control group and air pneumoperitoneum group. (2) After 24 h, the serum level of IL-6 was statistically lower in the CO₂ pneumoperitoneum group compared to the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. There was no statistical significance among the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. After 48 h, there was no statistical significance among the four groups. (3) After 24 h and 48 h, the serum level of IL-2 was statistically lower in the CO₂ pneumoperitoneum group compared to the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. There was no statistical significance among the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. (4) After 24 h and 48 h, the ascites levels of TNF-a was statistically lower in the CO₂ pneumoperitoneum group compared to the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. There was no statistical significance among the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. (5) After 24 h and 48 h, the phagocytic rate was statistically lower in the CO₂ pneumoperitoneum group compared to the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group.There were no statistical significance among the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. (6) After 24 h and 48 h, the phagocytic index was statistically lower in the CO₂ pneumoperitoneum group compared to the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group.There was no statistical significance among the control group, air pneumoperitoneum group and nitrogen pneumoperitoneum group. (7) After 24 h and 48 h, there was no significant difference of the pathologic changes among the four groups, however, the pathologic changes was more severe After 48 h than 24 h.CONCLUSION: (1) Humoral immunity was statistically suppressed during laparoscopy with CO₂ pneumoperitoneum compared to air pneumoperitoneum, nitrogen pneumoperitoneum and gasless technique.(2) The function of phagocytes was statistically reduced during laparoscopy with CO₂ pneumoperitoneum compared to air pneumoperitoneum,nitrogen pneumoperitoneum and gasless technique.(3) The effect of CO₂ pneumoperitoneum on the pathologic changes with infection is not significantly different with the effect of air pneumoperitoneum, nitrogen pneumoperitoneum and gasless technique.(4) Under condition of preexisting abdominal infection, CO₂ pneumoperitoneum statistically suppressed humoral immunity and reduced the function of phagocytes compared to air pneumoperitoneum ,nitrogen pneumoperitoneum and gasless technique,which increased the risk of infection proliferation and bacteria translocation.