title: Effects of different pressure levels of CO2 pneumoperitoneum on liver regeneration after liver resection in a rat model.
abstract: BACKGROUND
  A recent study demonstrated that high pressure of carbon dioxide (CO2) pneumoperitoneum before liver resection impairs postoperative liver regeneration. This study was aimed to investigate effects of varying insufflation pressures of CO2 pneumoperitoneum on liver regeneration using a rat model.
  
  
  METHODS
  180 male Wistar rats were randomly divided into three groups: control group (without preoperative pneumoperitoneum), low-pressure group (with preoperative pneumoperitoneum at 5 mmHg), and high-pressure group (with preoperative pneumoperitoneum at 10 mmHg). After pneumoperitoneum, all rats were subjected to 70% partial hepatic resection and then euthanized at 0 min, 12 h, and on postoperative days (PODs) 1, 2, 4, and 7. Following outcome parameters were used: liver regeneration (liver regeneration rate, mitotic count, Ki-67 labeling index), hepatocellular damage (serum aminotransferases), oxidative stress [serum malondialdehyde (MDA)], interleukin-6 (IL-6), and hepatocyte growth factor (HGF) expression in the liver tissue.
  
  
  RESULTS
  No significant differences were observed for all parameters between control and low-pressure groups. The liver regeneration rate and mitotic count were significantly decreased in the high-pressure group than in control and low-pressure groups on PODs 2 and 4. Postoperative hepatocellular damage was significantly greater in the high-pressure group on PODs 1, 2, 4, and 7 compared with control and/or low-pressure groups. Serum MDA levels were significantly higher in the high-pressure group on PODs 1 and 2, and serum IL-6 levels were significantly higher in the high-pressure group at 12 h and on POD 1, compared with control and/or low-pressure groups. The HGF tissue expression was significantly lower in the high-pressure group at 12 h and on PODs 1 and 4, compared with that in control and/or low-pressure groups.
  
  
  CONCLUSIONS
  High-pressure pneumoperitoneum before 70% liver resection impairs postoperative liver regeneration, but low-pressure pneumoperitoneum has no adverse effects. This study suggests that following laparoscopic liver resection using appropriate pneumoperitoneum pressure, no impairment of liver regeneration occurs.
authors.affiliation: Department of Gastroenterological and Pediatric Surgery, Oita University Faculty of Medicine, 1-1 Idaigaoka, Hasama-machi, Yufu, Oita, 879-5593, Japan, komorin@oita-u.ac.jp.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Komori
authors.forename: Yukio
authors.initials: Y
authors.lastname: Iwashita
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ohta
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kawano
authors.forename: Masafumi
authors.initials: M
authors.lastname: Inomata
authors.forename: Seigo
authors.initials: S
authors.lastname: Kitano
mesh_terms: D000818:Animals; D002245:Carbon Dioxide; D006498:Hepatectomy; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism; D015850:Interleukin-6 / Q000097:blood; D019394:Ki-67 Antigen / Q000378:metabolism; D010535:Laparoscopy; D008099:Liver / Q000378:metabolism; D008115:Liver Regeneration; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008940:Mitotic Index; D023421:Models, Animal; D018384:Oxidative Stress; D011028:Pneumoperitoneum, Artificial / Q000379:methods*; D011897:Random Allocation; D017208:Rats, Wistar; D000637:Transaminases / Q000097:blood
chemical_list: D015850:Interleukin-6; D019394:Ki-67 Antigen; C498355:Mki67 protein, mouse; D002245:Carbon Dioxide; D008315:Malondialdehyde; D017228:Hepatocyte Growth Factor; D000637:Transaminases