title: Laparoscopic surgery induced interleukin-6 levels in serum and gut mucosa: implications of peritoneum integrity and gas factors.
abstract: BACKGROUND
  The peritoneum serves as an integral part of host immunity, and the homeostasis of intraperitoneal environment is held to be beneficial for patient recovery after abdominal surgery. How minimal invasive access to the abdomen by laparoscopy and incisions would alter the intraperitoneal immune response is not fully defined. This study examined the levels of IL-6 in serum and gut mucosa following laparoscopic surgery with reference to the peritoneum integrity and gas factors.
  
  
  METHODS
  BALB/c mice were divided into three groups (ten animals in each group) that underwent different abdominal surgical treatments: laparotomy (open group), laparoscopy with atmospheric air (air group) or carbon dioxide pneumoperitoneum (CO(2) group). A 3-cm incision of the skin and muscle was made in all animals except the peritoneum was left intact in the latter two animal groups in order to cancel out the incisional tissue injury present in laparotomy. Four hours after surgery, serum, and jejunal mucosa were extracted for IL-6 measurement by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  Open laparotomy resulted in significant elevation of serum IL-6 level when compared to the laparoscopic procedures in the descending order of open > air > CO(2) groups. For the mucosal IL-6 level, both the open and air groups were significantly higher than the CO(2) group. Data from multivariate analysis revealed that breaching or incision of the peritoneum was an important factor for the elevated levels of IL-6 in serum (p < 0.001) and jejunal mucosa (p = 0.032).
  
  
  CONCLUSIONS
  The present study suggests that laparoscopic techniques to minimize the size of the peritoneal incision as well as exposure to atmospheric air can potentially reduce postoperative stress responses associated with abdominal surgery and prompt early recovery.
authors.affiliation: Department of Surgery, LKS Faculty of Medicine, Queen Mary Hospital, University of Hong Kong Medical Centre, 102 Pokfulam Road, Pokfulam, Hong kong.
authors.forename: John M
authors.initials: JM
authors.lastname: Luk
authors.forename: Peter H
authors.initials: PH
authors.lastname: Tung
authors.forename: Kwong-Fai
authors.initials: KF
authors.lastname: Wong
authors.forename: Kwong-Leung
authors.initials: KL
authors.lastname: Chan
authors.forename: Simon
authors.initials: S
authors.lastname: Law
authors.forename: John
authors.initials: J
authors.lastname: Wong
mesh_terms: D000388:Air; D000818:Animals; D002245:Carbon Dioxide; D015850:Interleukin-6 / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007583:Jejunum / Q000378:metabolism*; D010535:Laparoscopy; D007813:Laparotomy; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010537:Peritoneum / Q000473:pathology* / Q000601:surgery; D011028:Pneumoperitoneum, Artificial / Q000379:methods*
chemical_list: D015850:Interleukin-6; D002245:Carbon Dioxide