title: The impact of carbon dioxide pneumoperitoneum on liver regeneration after liver resection in a rat model.
abstract: BACKGROUND
  In recent years, laparoscopic hepatic resection is performed by an increasing number of surgeons. Despite many advantages of the laparoscopic procedure, it is unclear whether the pneumoperitoneum affects the postoperative liver regeneration after liver resection. The current study aimed to investigate the influence of a carbon dioxide (CO(2)) pneumoperitoneum on liver regeneration in a rat model.
  
  
  METHODS
  In this study, 60 male Wistar rats were subjected to 70% partial hepatic resection. Of these 60 animals, 30 underwent preoperative pneumoperitoneum at 9 mmHg for 60 min. After hepatic resection, the rats were killed at 12, 24, and 48 h, and on days 4 and 7. The outcome parameters were hepatocellular injury (plasma aminotransferases), oxidative stress (plasma malondialdehyde), interleukin-6 (IL-6), and liver regeneration (mitotic index, KI-67; regenerating liver mass).
  
  
  RESULTS
  The mitotic index was significantly lower in the pneumoperitoneum group than in the group without pneumoperitoneum at all time points (p < 0.05). In the pneumoperitoneum group, KI-67 was significantly lower on day 4 (p < 0.05). The liver regeneration rate was significantly lower for the animals with pneumoperitoneum on days 2 and 4 (p < 0.05). The postoperative hepatocellular injury was significantly greater after pneumoperitoneum at 12, 24, and 48 h (p < 0.05). Plasma malondialdehyde and IL-6 were significantly higher in the pneumoperitoneum group at 24 h and on day 4 (p < 0.05).
  
  
  CONCLUSIONS
  This study showed that pneumoperitoneum before extended liver resection impaired postoperative liver regeneration. Oxidative stress reaction and hepatocellular damage was markedly higher after pneumoperitoneum. Further investigations, especially with patients that have impaired liver function, are necessary for clinical consequences to be drawn from these results.
authors.affiliation: Clinic for General, Visceral, and Transplantation Surgery, Charité Campus Virchow Clinic, University of Medicine Berlin, Berlin, Germany. sven.schmidt@charite.de
authors.forename: S C
authors.initials: SC
authors.lastname: Schmidt
authors.forename: G
authors.initials: G
authors.lastname: Schumacher
authors.forename: N
authors.initials: N
authors.lastname: Klage
authors.forename: S
authors.initials: S
authors.lastname: Chopra
authors.forename: P
authors.initials: P
authors.lastname: Neuhaus
authors.forename: U
authors.initials: U
authors.lastname: Neumann
mesh_terms: D000818:Animals; D002245:Carbon Dioxide; D005740:Gases; D006498:Hepatectomy; D010535:Laparoscopy; D008099:Liver / Q000503:physiopathology*; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D023421:Models, Animal; D018384:Oxidative Stress; D011028:Pneumoperitoneum, Artificial / Q000009:adverse effects*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D005740:Gases; D002245:Carbon Dioxide