Hypertonicity of dialysis fluid suppresses intraperitoneal inflammation

We studied acute and chronic intraperitoneal inflammation during dialysis performed in rats injected with phosphate-buffered saline alone (PBS) or PBS supplemented with glucose (Glu) or with mannitol (Man). In acute experiments, the result of a first dialysis with PBS in every rat (dialysis I) was compared with a second dialysis performed 24 hours later (dialysis II) using a different dialysis fluid: either PBS with 3.86 g/dL Man or PBS with 3.86 g/dL Glu. In rats exposed to hypertonic dialysis solutions (both Glu and Man), inflammatory reaction was decreased (cell count: p < 0.05; nitric oxide secretion: p < 0.05; protein in dialysate: p < 0.05). In control animals treated only with PBS (dialysis I and dialysis II), the inflammatory reactions during dialysis I and dialysis II were comparable. In chronic experiments, rats were dialyzed with the tested fluids for four weeks. Weekly, dialysate samples were taken and analyzed. At the end of the study, cell counts and protein losses were higher in the PBS-treated rats than in the other groups (cell count: p < 0.05, Glu vs PBS, and p < 0.05, Man vs PBS; protein in dialysate: p < 0.001, Glu vs PBS, and p < 0.01, Man vs PBS). We conclude that hypertonicity of the dialysis fluid inhibits the inflammatory reaction in the peritoneal cavity during peritoneal dialysis.