Physiological and anti-inflammatory roles of dietary fiber and butyrate in intestinal functions.
BACKGROUND
We investigated the effects of pectin, a soluble dietary fiber, on the morphological parameters of the small intestine. In addition, we tested the effects of butyrate enemas on dextran sulfate sodium (DSS)-induced experimental colitis.


METHODS
Male Wistar rats were fed an elemental diet containing 2.5% pectin for 14 days, and several parameters were then determined. DSS-induced colitis was evoked by the oral administration of water containing 3% DSS for 10 days. The butyrate enema (3 mL of 100 mmol/L butyrate per day) was begun 7 days before the DSS treatment. Interleukin (IL)-8 secretion in the human intestinal epithelial cell line HT-29 was determined by enzyme-linked immunosorbent assay (ELISA).


RESULTS
Pectin feeding induced a significant increase in the villus height and crypt depth in the small intestine. These effects correlated with a significant increase in plasma enteroglucagon levels. Pretreatment with a butyrate enema significantly blocked the development of DSS-induced experimental colitis. In the in vitro experiment, sodium butyrate dose-dependently inhibited tumor necrosis factor (TNF)-alpha-induced IL-8 secretion in HT-29 cells.


CONCLUSIONS
A trophic effect due to dietary fiber was directly observed. The generation of short-chain fatty acids and the induction of enteroglucagon release might play an important role in this process. Butyrate, one of the major metabolites of dietary fiber, exerted a potent anti-inflammatory effect both in vivo and in vitro. Dietary fiber may therefore play important roles in the regulation of normal and pathological conditions in the intestine.
Andoh
A
A
Department of Internal Medicine, Shiga University of Medical Science, Seta-Tukinowa, Otsu, Japan.
Bamba
T
T
Sasaki
M
M
D000230:Adenocarcinoma / Q000188:drug therapy / Q000378:metabolism; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D000925:Anticoagulants / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000627:therapeutic use*; D000930:Antidiarrheals / Q000008:administration & dosage / Q000627:therapeutic use*; D002087:Butyrates / Q000008:administration & dosage / Q000627:therapeutic use*; D003092:Colitis / Q000139:chemically induced / Q000188:drug therapy* / Q000201:enzymology; D016264:Dextran Sulfate / Q000037:antagonists & inhibitors / Q000633:toxicity; D004043:Dietary Fiber / Q000627:therapeutic use*; D004733:Enema; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D007421:Intestine, Small / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010368:Pectins / Q000008:administration & dosage / Q000627:therapeutic use*; D009195:Peroxidase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000893:Anti-Inflammatory Agents; D000925:Anticoagulants; D000930:Antidiarrheals; D002087:Butyrates; D004043:Dietary Fiber; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D010368:Pectins; D016264:Dextran Sulfate; D009195:Peroxidase