Morphologic aspects of chronic peritoneal dialysis in a rat model

◆ Objective: We previously put forward an experimental model for evaluating peritoneal function in chronically dialyzed rats. In the present paper, we show the morphologic alterations detected by electron microscopy in the peritonea of chronically dialyzed rats. ◆ Materials and Methods: The study was done in male Wistar rats. Animals were divided into two groups: control (non dialyzed) rats and dialyzed rats [intraperitoneally exposed to Dianeal 3.86% (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.) for 1 month]. At the end of the study, the rats were humanely killed by bleeding, and samples of the visceral peritoneum covering the liver were taken from 3 rats in each group. The samples were examined by transmission electron microscopy (TEM). ◆ Results: In control rats, the peritoneum was composed of flattened mesothelial cells covering the thin layer of the submesothelial connective tissue (ST), containing few fibroblasts. In dialyzed animals, a dramatic expansion of the ST was found. We saw compartmentalization of the ST, with changed morphology of the fibroblasts, altered organization of collagen fibers, and changes in the cells infiltrating the ST. Apart from the fibroblasts, mast cells were relatively numerous. ◆ Conclusions: Our work underlines the capabilities of morphology studies in an animal model for assessing peritoneal dialysis fluid biocompatibility.