title: Does CO2 pneumoperitoneum alter the ultra-structuture of the mesothelium?
abstract: BACKGROUND
  Pneumoperitoneum may be responsible for ultra-structural alterations in the mesothelium during laparoscopy. To characterize the effect of pneumoperitoneum on the mesothelial cells with CO(2) and compressed air; and to compare to laparotomy and control group (anesthesia only).
  
  
  METHODS
  Forty C-57 mice were divided in four groups of 10 animals each: CO(2), air, laparotomy, and control group. The animals were submitted to pneumoperitoneum at 8 mmHg during 30 min (CO(2) or compressed air). Five animals of each group were sacrificed 2 and 24 h after the procedure. Fragments of parietal peritoneum were collected and processed for scanning electron microscopy.
  
  
  RESULTS
  Control group revealed uninterrupted mesothelial cells, without any evidence of cellular limits; close contact between the cells; absence of intercellular clefts and presence of microvilli. In the laparotomy group, similar results to the control group, with decreased microvilli were noted. Air pneumoperitoneum was associated with alterations in the morphology of the mesothelial cells, clear cellular limits, and cells with spherical and fusiforme formats. CO(2) pneumoperitoneum showed mesothelial cells with clear cellular limits, predominantly spherical cellular format, and intercellular clefts that allowed the visualization of the exposed basal membrane. These alterations were more intense after 24 h. There was a statistical significance between CO(2) group (2 and 24 h) compared to the control group and laparotomy for cellular limits, intercellular clefts and microvilli, P < 0.0001.
  
  
  CONCLUSIONS
  Pneumoperitoneum causes damage in the mesothelial ultra-structure, which differs from the laparotomy group. CO(2) pneumoperitoneum is more harmful to the mesothelium than the air.
authors.affiliation: Department of Gastroenterology, University of São Paulo, São Paulo, Brazil.
authors.forename: Marcos T A
authors.initials: MT
authors.lastname: Rosário
authors.forename: Ulysses
authors.initials: U
authors.lastname: Ribeiro
authors.forename: Carlos E P
authors.initials: CE
authors.lastname: Corbett
authors.forename: Alberto C
authors.initials: AC
authors.lastname: Ozaki
authors.forename: Cláudio C
authors.initials: CC
authors.lastname: Bresciani
authors.forename: Bruno
authors.initials: B
authors.lastname: Zilberstein
authors.forename: Joaquim J
authors.initials: JJ
authors.lastname: Gama-Rodrigues
mesh_terms: D000388:Air; D000818:Animals; D002245:Carbon Dioxide; D004195:Disease Models, Animal; D004848:Epithelium / Q000473:pathology / Q000648:ultrastructure; D010535:Laparoscopy / Q000009:adverse effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D010537:Peritoneum / Q000473:pathology* / Q000648:ultrastructure; D011027:Pneumoperitoneum / Q000209:etiology* / Q000473:pathology*; D011312:Pressure; D013314:Stress, Mechanical
chemical_list: D002245:Carbon Dioxide