Influence of surface-active food additives on the integrity and permeability of rat intestinal mucosa

The influence of two surface-active food additives on the integrity and permeability of rat ileal mucosa has been studied. We determined the activity of N-acetyl-beta-glucosaminidase, a lysosomal enzyme, in the rat intestinal lumen after deposition of polyoxyethylene (20) sorbitan monostearate (polysorbate 60; Tween 60) or polyoxyethylene (20) sorbitan monooleate (polysorbate 80; Tween 80) in a section of ligated, cannulated gut. We also determined the activities of N-acetyl-beta-glucosaminidase, alkaline phosphatase, 5'-nucleotidase and phospholipase A2 in mixtures of isolated mucosal cells and polysorbate 60 or polysorbate 80. The activity of N-acetyl-beta-glucosaminidase was increased in the luminal contents of the cannulated gut 15 min after deposition of either polysorbate 60 or polysorbate 80 (10 mg/ml fluid instilled into gut). It was also increased in mixtures of mucosal cells and polysorbate 60 or polysorbate 80 (0.1-10 mg/ml). In contrast, the activities of alkaline phosphatase and 5'-nucleotidase were unaffected and that of phospholipase A2 was decreased by the presence of either polysorbate. These findings indicated that polysorbate 60 and polysorbate 80 released lysosomal enzymes from the intestinal mucosal cells and that these agents might damage the intestinal mucosa and increase its permeability. We therefore determined the intestinal permeability to sodium fluorescein in the absence and presence of polysorbate 60 or 80 and found that the permeability was slightly increased in the presence of either of the compounds at concentrations of 10 mg/ml fluid instilled into gut. It is possible therefore that surface-active food additives might impair the function of the mucosal barrier and increase the permeability of the gut to potentially toxic and pathogenic molecules.