Background: Chronic stress affects the course of inflammatory bowel disease and experimental colitis, and may also initiate intestinal inflammation in rats. Aim: To investigate the effects of stress on the M cell containing follicle associated epithelium, specialised in antigen uptake. Subjects and methods: Wistar rats were submitted to acute water avoidance stress for one hour or chronic water avoidance stress for 1 hour/day for 10 consecutive days. Permeability to 51 Cr-EDTA, horseradish peroxidase, and chemically killed Escherichia coli K-12 was studied in both villus and follicle associated epithelium in Ussing chambers. Segments were further examined by light, electron, and confocal microscopy. Results: Acute stress increased horseradish peroxidase flux in villus as well as in follicle associated epithelium. Chronic stress further increased permeability to horseradish peroxidase in villus and follicle associated epithelium, in the latter by almost fourfold. Moreover, chronic stress induced over 30 times increased E coli passage in follicle associated epithelium whereas there was no significant increase in villus epithelium. Bacterial uptake was confirmed by confocal microscopy showing fluorescent bacteria penetrating and passing through the epithelial surface. Conclusions: These results show that the barrier function of follicle associated epithelium can be modulated, and that chronic stress enhances the uptake of luminal antigens and bacteria via the follicle associated epithelium. This can increase antigen exposure in Peyer's patches thereby having implications in the initiation of proinflammatory immune responses within the intestinal mucosa.
Endoscopic biopsies of human colon are viable in Ussing chambers and are reliable tools for studies of mucosal permeability to protein antigens. The technique offers a broad potential for studies of mucosal function in the pathophysiology of human gastrointestinal diseases.
Objective: Early postoperative enteral feeding has been reported to stimulate intestinal mucosa proliferation. Dietary components influence the intestinal adaptive response after resection and glutamine is a preferential nutrient to enterocytes. The purpose of this study was to evaluate the effects of bolus glutamine supplementation on intestinal adaptation. Methods: Male Wistar rats underwent a 65% small bowel resection. The rats were divided into three groups receiving glutamine 2 g/kg/day, isonitrogenous glycine or saline by gavage for 10 days. All the rats were provided with ordinary rat chow ad libitum. Sampling was done 10 days after resection. Animals fed ordinary rat chow without surgery or specific treatment served as control. Results: Mucosal wet weight, DNA, RNA, protein contents and sucrose activity, as well as villus height increased in the ileal remnant. No significant differences in any of these parameters or body weight could be found between the three groups. Conclusion: Postoperative enteral bolus glutamine supplementation at a dose of 2 g/kg b.w. did not enhance the adaptation of the residual intestine 10 days after massive intestinal resection in the rat.
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