D-Xylose Assay

INTRODUCTION

The transport of molecules from the gut into the body occurs either in between the cells or through the cells, paracellularly or transcellularly,respectively. Fluorescent-labeled dextrans can be used to evaluate paracellular permeability, while D-xylose, a simple monosaccharide,

can be used to evaluate transcellular uptake.

However, it may be necessary to use two different markers to evaluate permeability. For example, two groups of rats fed total parenteral nutrition supplemented with two different amino acid cocktails showed an increase in fluorescein isothiocyanate (FITC)-labeled dextran

permeability in one group over the other, but no discernible difference in D-xylose uptake between the two groups (1). This data shows that measuring only one mode of transport may result in incorrect conclusions about permeability.

Chondrex provides a D-xylose assay kit in a convenient 96-well plate format (catalog # 6601), as well as FITC-labeled dextrans (catalog# 4009:4 kDa, 4013:40 kDa) for the evaluation of intestinal permeability in-vitro or in-vivo. Rhodamine-labeled dextran (catalog # 4014:70 kDa), which fluoresces at a different wavelength than FITC, is also available, permitting the simultaneous use of two different sized dextrans. Moreover, Chondrex offers an array of anti-bacteria and anti-lipopolysaccharides (LPS) antibody assay kits as an alternative method for evaluating gut barrier integrity, and proper immune function against these environmental factors.