2005 Abstracts: Two Mechanisms Mediate the Anti-Inflammatory Effects of Laparoscopy: Metabolic and Mechanical
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Two Mechanisms Mediate the Anti-Inflammatory Effects of Laparoscopy: Metabolic and Mechanical
Alexander R. Aurora, Joseph M. Fuentes, Eric J. Hanly, Samuel P. Shih, Antonio De Maio, Mark A. Talamini, Johns Hopkins University, Baltimore, MD
Introduction:Laparoscopic surgeons employ the use of the carbon dioxide (CO2) pneumoperitoneum daily. Little evidence exists to explain the mechanism by which the laparoscopic approach benefits the patient. The literature suggests that CO2 may have anti-inflammatory effects. We investigated the effect of CO2 and the pneumoperitoneum on the LPS-induced inflammatory response in rats over time.
Methods:Rats were randomized into 4 groups: LPS, Isoflurane, CO2, and Helium (He). Experimental groups underwent 30 minutes of anesthesia with or without a pneumoperitoneum of CO2 or He. All groups received E. coli bacterial endotoxin (LPS) 1mg/kg i.v. at the end of the experimental condition. Control rats received LPS alone. All groups had saline matched controls. Blood samples were taken for cytokine analysis (TNF-α, IL-6, IL-10) at 60, 90 and 120 minutes after LPS administration. Results:TNF-α was decreased by both the CO2 and the He pneumoperitoneum at 60 and 90 minutes compared to the LPS group (n=5, p<0.01). Similarly, both the CO2 and the He pneumoperitoneum attenuated IL-6 production at 90 minutes compared to LPS (n=5, p<0.01). These results suggest a mechanical effect of the pneumoperitoneum independent of the gas used. Alternatively, the CO2 pneumoperitoneum but not the He pneumoperitoneum significantly increased IL-10 at 60 minutes in comparison to LPS alone (n=5, p<0.01), suggesting a CO2-specific effect. Conclusion:We have teased out an as yet unidentified dual effect of the CO2 pneumoperitoneum. Our results suggest that the anti-inflammatory effects of laparoscopic surgery are due in part to CO2 and in part to the physical distension of the peritoneal cavity created by the pneumoperitoneum. Preliminary data suggest that CO2 acts via acidosis of peritoneal macrophages whereas the pneumoperitoneum exerts its effect via the vagus nerve.| TNF-a | IL-6 | IL-10 | |||||||
| 60 min | 90 min | 120 min | 60 min | 90 min | 120 min | 60 min | 90 min | 120 min | |
| LPS | 9778 | 18641 | 9782 | 0 | 1564 | 10287 | 756 | 1147 | 558 |
| Isoflurane | 6662 | 26163 | 6270 | 0 | 1024 | 12830 | 724 | 1100 | 1635 |
| CO2 | 2914** | 6448** | 3874 | 0 | 264** | 8947 | 1650** | 725 | 946 |
| Helium | 2477** | 8733** | 6926 | 0 | 305** | 8715 | 527 | 612 | 905 |
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