Ultrastructure of basement membranes of peritoneal capillaries in a chronic peritoneal infusion model in the rat

Background. Long-term peritoneal dialysis with glucose-based dialysis solut ions has been associated with diabetiform alterations of peritoneal tissue. A peritoneal infusion model in the rat was developed to study the effect o f chronic infusion of a glucose-based dialysis solution and an isotonic non -glucose solution on the ultrastructure of the basement membranes of perito neal capillaries. The effect of ageing was also studied in an untreated con trol group. Methods. A vascular access port (Rat-o-Port) with attached peritoneal cathe ter was implanted subcutaneously in the neck of nine male Wistar rats. The rats were divided randomly into three groups: the glucose group (n = 3) was infused daily for 20 weeks with 60 ml/kg body weight 3.86% glucose solutio n. A control group (n = 2) was infused daily for 20 weeks with 60 ml/kg bod y weight Ringer's lactate. The untreated control group (n = 4) was studied at the onset of the experiment and after 20 weeks. Omental tissue was obtai ned from each rat at the end of the experimental period for ultrastructural examination. Results. Extensive lamination of basement membranes of omental capillaries was found in the glucose group. This was in contrast to the untreated contr ol group where clear, single basement membranes were seen at the onset of t he experiment and after 20 weeks. These latter findings were similar to tho se in the Ringer's lactate group. Conclusions. The chronic infusion model in the rat is suitable for the inve stigation of the effects on the ultrastructure of peritoneal capillaries of chronic exposure to dialysis fluids. The duplications of basement membrane s of omental capillaries found in the glucose group show a striking resembl ance to those found in long-term peritoneal dialysis patients. This suggest s a role for glucose in the development of peritoneal ultrastructural alter ations found in longterm peritoneal dialysis.