Innovative Methodology Correlating structure with solute and water transport in a chronic model of peritoneal inflammation

Flessner, Michael F., Jaehwa Choi, Heather Vanpelt, Zhi He, Kimberly Credit, Jeffrey Henegar, and Michael Hughson. Correlating structure with solute and water transport in a chronic model of peritoneal inflammation. Am J Physiol Renal Physiol 290: F232–F240, 2006. First published August 23, 2005; doi:10.1152/ajprenal.00211.2005.—To study the process of chronic peritoneal inflammation from sterile solutions, we established an animal model to link structural changes with solute and water transport. Filtered solutions containing 4% N-acetylglucosamine (NAG) or 4% glucose (G) were injected intraperitoneally daily in 200to 300-g rats and compared with controls (C). After 2 mo, each animal underwent transport studies using a chamber affixed to the parietal peritoneum to determine small-solute and protein mass transfer, osmotic filtration, and hydraulic flow. After euthanasia, parietal tissues were sampled for histological analysis, which demonstrated significant differences in peritoneal thickness ( m; C, 42.6 7.5; G, 80.4 22.3; NAG, 450 104; P 0.05). Staining for VEGF correlated with CD-31 vessel counts (no./mm: C, 53.1 16.1; G, 166 32; NAG, 183 32; P 0.05 ). Tissue analysis showed treatment effects on tissue hyaluronan ( g/g: C, 962 73; G, 1,169 69; NAG, 1,428 69; P 0.05) and collagen ( g/g: C, 56.9 12.0; G, 107 12; NAG, 97.6 11.4; P 0.05) but not sulfated glycosaminoglycan. Transport experiments revealed no significant differences in mannitol transfer or osmotic flow. Changes were seen in hydrostatic pressure-driven flux ( l min 1 cm : C, 0.676 0.133; G, 0.317 0.124; NAG, 0.284 0.117; P 0.05) and albumin transfer ( l min 1 cm : C, 0.331 0.028; G, 0.286 0.026; NAG, 0.229 0.025; P 0.04). We conclude that alteration of the interstitial matrix correlates with diminished hydraulic conductivity and macromolecular transport.