Microflora-derived polyamines modulate obstruction-induced colonic mucosal hypertrophy.
Experiments were designed to determine the role of microflora-derived intraluminal polyamines in the colonic mucosal response to obstruction. Sprague-Dawley rats were treated per os with 0.9% NaCl or a combination of nonabsorbable antibiotics prior to the placement of either a sham or complete colonic obstruction. Sixty-six hours after surgery, wet tissue weight, DNA, RNA, and protein content were all increased in the mucosa proximal to the obstruction in NaCl-treated animals; however, DNA content was the only parameter increased after antibiotics. This induction was a purely local effect as neither hyperplasia nor hypertrophy was observed in the ileum or colon distal to the obstruction. In the NaCl-treated animals, mucosal ornithine decarboxylase activity was not induced until 48 h postsurgery, yet mucosal spermidine concentrations were significantly higher as early as 24 h. Intraluminal bacterial lysine, ornithine, and arginine decarboxylase activities were induced by obstruction but were reduced by antibiotic treatment. [14C]putrescine uptake by intestinal epithelial cells (IEC-6) in culture was blocked by the antibiotics employed in this study, but [14C]-lysine transport was relatively unaffected. These data demonstrate that intraluminal polyamines modulate the trophic response of the colonic mucosa after colonic obstruction.
Osborne
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Department of Physiology, School of Medicine, East Carolina University, Greenville, North Carolina 27858.
Seidel
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D000818:Animals; D001414:Bacitracin / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000201:enzymology*; D002262:Carboxy-Lyases / Q000378:metabolism; D003106:Colon / Q000382:microbiology / Q000473:pathology*; D004359:Drug Therapy, Combination / Q000494:pharmacology; D006984:Hypertrophy; D007413:Intestinal Mucosa / Q000382:microbiology / Q000473:pathology*; D007415:Intestinal Obstruction / Q000473:pathology*; D008297:Male; D009355:Neomycin / Q000494:pharmacology*; D009955:Ornithine Decarboxylase / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism*; D011112:Polymyxin B / Q000494:pharmacology*; D011113:Polymyxins / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D011073:Polyamines; D011113:Polymyxins; D001414:Bacitracin; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase; C021520:lysine decarboxylase; C019722:arginine decarboxylase; D009355:Neomycin; D011112:Polymyxin B