title: Immune cell populations and cytokine production in spleen and mesenteric lymph nodes after laparoscopic surgery versus conventional laparotomy in mice.
abstract: OBJECTIVE
  There is evidence that open as well as minimally invasive abdominal surgery impair post-operative innate and acquired immune function. To compare the impact of these approaches as well as the one of different peritoneal gas exposures on immune function, we investigated cellular as well as cytokine-based immune parameters in mesenteric lymph nodes and the spleen postoperatively.
  
  
  METHODS
  Mice (n = 26) were randomly assigned to the 4 study groups: (1) sham controls undergoing anesthesia alone, (2) laparotomy, and (3) air, or (4) carbon dioxide pneumoperitoneum. Mice were sacrificed 48 h after the intervention, and their spleens and mesenteric lymph nodes were harvested. Cytokine production (TNF-α, IL-6, IL-10, and IFN-γ), splenic T cell subpopulations (cytotoxic T cells, T helper cells, and regulatory T cells) were analyzed.
  
  
  RESULTS
  TNF-α production of splenocytes 16 h after ex vivo lipopolysaccharides (LPS) stimulation was significantly increased in the laparotomy group compared to all other groups. In contrast, TNF-α production of lymph node cells and IL-6 production of splenocytes after ex vivo LPS stimulation did not differ significantly between the groups. The numbers of regulatory T cells (Treg) in the spleen differed between groups. A significant reduction in Treg cell frequency was detected in the CO(2) insufflation group compared to the laparotomy and the air insufflation group.
  
  
  CONCLUSIONS
  Our findings demonstrate a distinct difference in immune effector functions and cellular composition of the spleen with regard to splenic TNF-α production and increased numbers of Treg cells in the spleen. These findings are in line with a higher peritoneal inflammatory status consequent to peritoneal air rather than CO(2) exposure. Treg turned out to be key modulators of postoperative dysfunction of acquired immunity.
authors.affiliation: Department of Pediatric Surgery, University Children's Hospital Zurich, Steinwiesstr. 75, 8032, Zurich, Switzerland. ueli.moehrlen@kispi.uzh.ch
authors.forename: Ueli
authors.initials: U
authors.lastname: Moehrlen
authors.forename: Anja
authors.initials: A
authors.lastname: Lechner
authors.forename: Monika
authors.initials: M
authors.lastname: Bäumel
authors.forename: Karin
authors.initials: K
authors.lastname: Dostert
authors.forename: Johann
authors.initials: J
authors.lastname: Röhrl
authors.forename: Martin
authors.initials: M
authors.lastname: Meuli
authors.forename: Daniela N
authors.initials: DN
authors.lastname: Männel
authors.forename: Jürg
authors.initials: J
authors.lastname: Hamacher
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D016207:Cytokines / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D010535:Laparoscopy; D007813:Laparotomy; D008198:Lymph Nodes / Q000166:cytology* / Q000276:immunology*; D008643:Mesentery / Q000166:cytology* / Q000276:immunology*; D051379:Mice; D011028:Pneumoperitoneum, Artificial; D011897:Random Allocation; D013154:Spleen / Q000166:cytology* / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D016207:Cytokines