Supplementation and inhibition of nitric oxide synthesis influences bacterial transit time during bacterial translocation in rats.
In the obstructed gut, nitric oxide (NO) may influence intestinal barrier function and translocation of bacteria. By using a novel experimental approach, we investigated the effect of supplementation and inhibition of NO synthesis on the time interval necessary for translocation of green fluorescent protein-transfected Escherichia coli (GFP-uv E. coli) in a rat model of small bowel obstruction. In anesthetized Wistar rats, 4 x 10(8) GFP-uv E. coli were administered into a reservoir of terminal ileum formed by ligature. Animals were randomized to receive either i.v. arginine (10 mg/kg), aminoguanidine (300 mg/kg), L-NAME (25 mg/kg), or saline (control). Translocation of GFP-uv E. coli was assessed using intravital video microscopy. Minimal transit time of translocation was measured as time from injection of GFP-uv E. coli into the gut lumen until bacteria were observed in the lamina submucosa and as time from injection of bacteria into the gut lumen until bacteria were observed in the lamina muscularis propria. Minimal transit times were expressed as mean +/- SD. Bacterial translocation into the submucosa and muscularis propria took 36 +/- 7 min and 81 +/- 9 min, respectively in control animals receiving saline. Aminoguanidine and L-NAME caused a marked delay of minimal transit time into the submucosa (63 +/- 5 min and 61 +/- 7 min, respectively; P < 0.05). Arginine significantly accelerated bacterial translocation into the muscularis propria (61 +/- 9 min, P < 0.05). GFP-uv E. coli were detected on frozen sections of small bowel, mesentery, liver, and spleen 2 h after GFP-uv E. coli administration in all animals. A marked upregulation of inducible NO synthase (NOS) in the obstructed bowel segment was demonstrated on immunohistochemistry. The assessment of a newly defined parameter, minimal bacterial transit time, may serve as an additional functional aspect of intestinal barrier function for pathophysiological and pharmacological studies. Aminoguanidine, L-NAME, and arginine were effective in influencing minimal transit time of E. coli during small bowel obstruction.
Samel
Stephan
S
Department of Surgery, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany.
Keese
Michael
M
Lanig
Sybille
S
Kleczka
Martha
M
Gretz
Norbert
N
Hafner
Mathias
M
Sturm
Jörg
J
Post
Stefan
S
D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D018988:Bacterial Translocation / Q000187:drug effects* / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004926:Escherichia coli / Q000737:chemistry / Q000502:physiology*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D006146:Guanidines / Q000494:pharmacology*; D007077:Ileal Diseases / Q000150:complications / Q000382:microbiology*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000382:microbiology; D007415:Intestinal Obstruction / Q000150:complications / Q000382:microbiology*; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D008297:Male; D023421:Models, Animal; D009130:Muscle, Smooth / Q000187:drug effects / Q000382:microbiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014162:Transfection
D004791:Enzyme Inhibitors; D006146:Guanidines; D008164:Luminescent Proteins; D020030:Nitric Oxide Donors; D049452:Green Fluorescent Proteins; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; C004479:pimagedine; D019331:NG-Nitroarginine Methyl Ester