title: The impact of laparoscopy with carbon dioxide versus helium on immunologic function and tumor growth in a rat model.
abstract: BACKGROUND
  The pathogenesis of port site recurrences after laparoscopic surgery for malignant disease is still unknown. Whether different gases used to establish pneumoperitoneum have an influence on immunologic function and therefore on promotion of tumor growth has not yet been investigated.
  
  
  METHODS
  Tumor growth of colon adenocarcinoma DHD/K12/TRb was evaluated in a rat model after insufflation either with CO2 (n = 25) or helium (n = 25) and in a control group (n = 25). Tumor growth was measured subcutaneously and intraperitoneally 5 weeks after insufflation. Beside tumor growth, immunologic changes (peripheral leukocyte subpopulations, plasma levels of TNFalpha and IL-10) were evaluated during the perioperative course in all animals.
  
  
  RESULTS
  Subcutaneous tumor growth was promoted by the CO2 (99 +/- 55 mg; p < 0.01) compared to the helium (40 +/- 41 mg) and control groups (36 +/- 33 mg). Total intraperitoneal tumor weight was 718 +/- 690 mg in the CO2 group compared to the helium (549 +/- 233 mg) and control groups (521 +/- 221 mg). While peripheral leukocyte subpopulations only differed between the laparoscopic groups and the control group during the perioperative course, TNFalpha plasma levels were significantly decreased and IL-10 plasma levels significantly increased in the CO2 group compared to the helium and control groups in the postoperative course.
  
  
  CONCLUSIONS
  The insufflation of CO2 promotes tumor growth compared to the helium and control groups in a rat model. In addition, increased tumor growth was associated with a significant increase in IL-10 and a decrease in TNFalpha plasma levels.
authors.affiliation: Department of Surgery, Humboldt University of Berlin, Germany.
authors.forename: C A
authors.initials: CA
authors.lastname: Jacobi
authors.forename: F
authors.initials: F
authors.lastname: Wenger
authors.forename: R
authors.initials: R
authors.lastname: Sabat
authors.forename: T
authors.initials: T
authors.lastname: Volk
authors.forename: J
authors.initials: J
authors.lastname: Ordemann
authors.forename: J M
authors.initials: JM
authors.lastname: Müller
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology / Q000473:pathology*; D000818:Animals; D002245:Carbon Dioxide; D003110:Colonic Neoplasms / Q000276:immunology / Q000473:pathology*; D004195:Disease Models, Animal; D006371:Helium; D016753:Interleukin-10 / Q000097:blood; D010535:Laparoscopy; D008297:Male; D011028:Pneumoperitoneum, Artificial / Q000009:adverse effects / Q000379:methods*; D011677:Punctures; D051381:Rats; D011919:Rats, Inbred Strains; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
chemical_list: D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D002245:Carbon Dioxide; D006371:Helium