Effect of azithromycin on acute inflammatory lesions and colonic bacterial load in a murine model of experimental colitis.
BACKGROUND
The aim of this study was to investigate the effect of the macrolide antibiotic azithromycin on mucosal changes and colonic bacterial load in a murine model of colitis.


METHODS
Colitis was induced in CD1 mice using enema of 0.2% solution of dinitrofluorobenzene, combined with skin sensitization. Four experimental groups of animals (N = 10 per group) were treated with 50 mg/kg/day azithromycin (AZ) or metronidazole (MN) perorally, starting 24 h before (AZ-1, MN-1) or 6 h after (AZ+1, MN+1) induction of colitis and for consecutive 5 days. Additional experimental mice group was treated with 10 mg/kg/day methylprednisolone intraperitoneally after induction of experimental colitis in the same manner (MP). Two control groups consisted of healthy animals (C) that received the challenge enema with phosphate-buffered saline (PBS) and animals with experimental colitis (chall) treated with equivolume of PBS perorally. Clinical score (0-5) and histopathologic score (0-30) were used to assess inflammatory changes, and colon washings were used to determine changes in bacterial load.


RESULTS
The anti-inflammatory effect of azithromycin did not differ from the effect of methylprednisolone, when compared with control group with experimental colitis. Metronidazole did not show a significant anti-inflammatory effect. Number of colonic bacteria did not differ significantly between control and experimental groups of animals.


CONCLUSIONS
We documented the anti-inflammatory effect of azithromycin in a murine model of acute colitis, suggesting that effects were targeted to oxidative burst and on mucosal/bacterial interface, independent of luminal bacterial load. Further studies should be focused on effect of azithromycin on the role of bacterial biofilm in perpetuation of chronic intestinal inflammation.
Plesko
Sanja
S
Department for Clinical and Molecular Microbiology, Clinical Hospital Center, Zagreb, Croatia. sanja.plesko@gmail.com
Banić
Marko
M
Plecko
Vanda
V
Anić
Branimir
B
Brkić
Tomislav
T
Renata
Heinzl
H
Rotkvić
Ivo
I
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D017963:Azithromycin / Q000008:administration & dosage / Q000627:therapeutic use*; D003092:Colitis / Q000139:chemically induced / Q000188:drug therapy*; D003106:Colon / Q000382:microbiology*; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy*; D008297:Male; D008775:Methylprednisolone / Q000627:therapeutic use; D008795:Metronidazole / Q000627:therapeutic use; D051379:Mice; D013047:Specific Pathogen-Free Organisms
D000900:Anti-Bacterial Agents; D008795:Metronidazole; D017963:Azithromycin; D008775:Methylprednisolone