Acute oxidative stress induces peritoneal hyperpermeability, mesothelial loss, and fibrosis

We explored the acute and long-term effects of short-lived, intense oxidative stress on peritoneal permeability and structure, induced with intraperitoneal injection of the oxidant agent deoxycholate, in rats. Ten minutes after the experimental intervention, peritoneal dialysis, performed over an exposure time of 60 minutes, revealed an increased urea dialysate/plasma ratio, greater glucose absorption, increased albumin losses in the effluent dialysate, and a reduced ultrafiltration rate. Mesothelial-cell imprints taken from the anterior liver surface indicated a substantially decreased density in the cell population. After the recovery period of 30 days, all alterations were still evident. Additionally, macroscopic and histologic observations made at this time interval detected peritoneal fibrosis and sclerosis, characterized by peritoneal adhesions, wrapping of intestinal loops, and the presence of a layer of fibrous tissue dressing the cavitary aspect of the liver peritoneal envelope. This report describes a reproducible experimental model of peritoneal fibrosis induced by acute oxidative injury. On the basis of these findings, it may be speculated that functional and structural alterations observed in patients are related to long-term continuous exposure of the monolayer to oxidative injury resulting from the high concentrations of d-glucose present in peritoneal dialysis solutions.