Transperitoneal permeabilities to water and solutes are similar in different rodent species

Abstract

Mechanistic studies of alterations in peritoneal transport are facilitated by the development of transgenic mice, but the majority of transport studies have been carried out in rats. To correlate results between species, we hypothesized that mouse transport parameters, normalized to the peritoneal contact area, would be similar to those of the rat. To address this, we affixed small (~10mm dia.) plastic chambers to the serosa of the abdominal wall of anesthetized CD1 and C57bl mice. The chamber constrained transfer across the area of the chamber base and facilitated mixing, volumetric and concentration measurements versus time for mannitol, serum albumin, and osmotic and hydrostatic pressure-driven convection. The Mass Transfer Coefficient of mannitol (MTCM) and of serum albumin (MTCBSA), hydrostatic pressure driven flux (JP), osmotic filtration (JOSM) were calculated from the time-dependent volume and concentration data. All parameters have units of μ l/min/cm2 and were compared to previously derived parameters from SD rats with a one-way ANOVA. There were no significant differences in the following (mean × SE): MTCM (CD1, 3.20× .38, n=7; C57bl, 2.34× .41, n=6; rat 2.72× .25, n=19; NS), JP (CD1, 0.42× .19, n=6; C57bl, 0.45× .18, n=6; rat 0.51× .20, n=9; NS), or JOSM (CD1, 0.92× .35, n=6; C57bl, 0.49× .35, n=6; rat 1.72× .35, n=6; NS). Only the MTCBSA demonstrated statistical difference: (x102: CD1, 9.52× 2.34, n=6; C57bl, 6.73× 1.92, n=7; rat 12.4× .1.4, n=17; p=.05). We conclude that use of a transport chamber to eliminate the variable peritoneal transfer area normalizes calculated transport characteristics and facilitates comparison between rodent species.