title: Pulmonary phagocyte depression induced by an acid or alkaline solution in a rat model of peritonitis.
abstract: BACKGROUND
  Peritonitis is a surgical problem with a high mortality rate attributable to various complications, including respiratory infection. This complication is more common under certain conditions reflective of the origin of peritonitis, suggesting that the composition of the peritoneal fluid exerts an influence on the intensity of the macrophage and peritoneal response. To establish a correlation among macrophage function, absorption of bacteria from the peritoneal cavity, and the pH of the peritoneal fluid, we carried out this study.
  
  
  METHODS
  Thirty female Wistar rats were divided into three equal groups, all of which received infusions of 0.9% saline by parietal puncture. In group A (control), the saline pH was 7.0; in group B, it was 2.5; and in group C, it was 8.5. After 40 min, 0.25 mL of a suspension containing 10(11) colony-forming units of (99m)Tc-labeled Escherichia coli was infused by the same route. After another 40 min, samples of vena caval blood, spleen, liver, and lung were removed; the radioactivity was counted; bacterial absorption was determined; and the proportional radioactivity/g of tissue was calculated. The values were compared among the groups by the Student t-test, with the level of significance set at p < 0.05.
  
  
  RESULTS
  There was significantly greater bacterial absorption in group B than in group C (p = 0.004) but no differences in the numbers of bacteria in the liver and spleen. Bacteria were significantly more numerous in the peripheral blood in group B than in groups A and C (p = 0.04 for both). Pulmonary phagocytosis was significantly reduced in group B compared with group A (p = 0.008) and group C (p = 0.005).
  
  
  CONCLUSIONS
  Peritonitis associated with acidic conditions in the peritoneal cavity is correlated with a reduction in pulmonary phagocytosis and an increase in the numbers of nonphagocytized bacteria in the peripheral blood, possibly representing a direct or indirect cause of the higher incidence of pneumonia and sepsis in these individuals.
authors.affiliation: Postgraduate Surgical Laboratory, Medical School and Radioisotope Laboratory, Pharmaceutical School, Federal University of Minas Gerais, Minas Gerais, Brazil. idaraujo@medicina.ufmg.br
authors.forename: Ivana
authors.initials: I
authors.lastname: Duval-Araujo
authors.forename: Maria A
authors.initials: MA
authors.lastname: Guimarães Sarmiento
authors.forename: Giovanni C
authors.initials: GC
authors.lastname: Xavier Grossi
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Rodrigues Simal
authors.forename: Valbert Cardoso
authors.initials: VC
authors.lastname: do Nascimento
authors.forename: Simone O
authors.initials: SO
authors.lastname: Fernandes Diniz
mesh_terms: D000818:Animals; D001769:Blood / Q000382:microbiology; D004927:Escherichia coli Infections / Q000276:immunology*; D005260:Female; D008099:Liver / Q000382:microbiology; D008168:Lung / Q000276:immunology* / Q000382:microbiology; D010538:Peritonitis / Q000276:immunology*; D010586:Phagocytes / Q000276:immunology*; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000382:microbiology; D014684:Venae Cavae / Q000382:microbiology