Rat model of peritoneal fibrosis: preliminary observations

The aim of this study was to establish a rat model of peritoneal fibrosis. After insertion of peritoneal catheters into 18 rats, the rats were divided into three groups. All animals were dialyzed twice a day with 4.25% Dianeal containing heparin. Group 1 rats (control) received antibiotics (vancomycin and gentamicin) in each exchange: group 2 rats were inoculated with Escherichia coli (5 x 10(6) in 5 mL of saline) at the beginning of the study; group 3 rats were treated with antibiotics after Escherichia coli inoculation; they also received a second inoculation of Escherichia coli after the second week of the study. By the end of the second week, group 2 rats were sacrificed because of catheter problems. Group 1 and 3 rats were sacrificed after 4 weeks of dialysis. A weekly peritoneal equilibration test (PET) was performed in each rat. The comparison of the PET results from the beginning and end of the study showed an increased permeability to glucose (p < 0.05) and total protein (p < 0.05) in group 3, which was not noted in group 1. In histology samples there was only delicate fibrosis with cellular infiltration in the peritoneum in group 1 rats. These changes were much more prominent in group 3 rats. This study suggests that E. coli peritonitis causes peritoneal fibrosis in rats, but to have a sclerosing encapsulating peritonitis (SEP) model this experiment must be carried out for a longer time.