Changes in intestinal permeability and epithelial differentiation during inflammation in the rat.

We examined changes in gut permeability in a controlled model of inflammation produced in rats after infection with the nematode parasite, Nippostrongylus brasiliensis. The probe, 51Cr-EDTA, was injected into ligated loops of jejunum in vivo and recovery of radioactivity was measured in urine, kidney, and intact loop at five hours. Urinary recovery was significantly increased during the early (day 7) and acute (day 10) stages of the infection compared with values in control rats but subsequently returned to normal. Urinary clearance of the probe after iv injection was unaltered during infection. Villus atrophy occurred only at the stage, whereas crypt hyperplasia was evident at both the early and acute stages. The terminal ileum appeared normal and showed normal permeability when compared with controls. We conclude that permeability changes are local to the site of inflammation, are reversible after healing and may be related to an increase in the proportion of relatively undifferentiated epithelium.