In vivo peritoneal chamber: linking structure and transport function

The present study aimed to develop an animal model of chronic peritoneal exposure that directly links transport with the tissue involved.

Daily, rats were intraperitoneally infused through subcutaneous ports with 20 mL of these solutions: isotonic Krebs (K), K + 2.5% mannitol (M), K + 2.5% N-acetylglucosamine (NAG). Controls included catheter-only (CC) and age-control rats (AC). After 2 months, each rat was anesthetized and a plastic chamber was affixed to the abdominal wall serosa to isolate a portion of the peritoneum for transport studies. In the first 90 minutes, a hypertonic solution (approximately 500 mosm/kg) containing 14C-mannitol was placed in chamber. The volume and 14C concentration were measured to determine the rate of osmotic flux (flow/Area(chamber)) into the chamber and the flux of mannitol from the chamber to the tissue. At 90 minutes, fluorescein isothiocyanate conjugate (FITC)-albumin was given intravenously. The rate of appearance of that substance in the chamber was measured over a period of 180 minutes and divided by Area(chamber) to determine the average flux. After the rat was humanely killed, the tissue under the chamber was collected for analysis of its hyaluronan concentration ([HA]).

All data are given as mean +/- standard error: [table: see text].

In the present pilot study, no significant correlations were observed, but the number of animals in each group was small (n = 3-4). Nevertheless, the results demonstrate the ability of the chamber technique to determine transperitoneal transport of water, small solutes, and protein, and to link those values directly to the structure of the tissue lying below the chamber. Thus, chronic treatment can be directly correlated with peritoneal structure and transport function.