COLONIC NITRITE AND IMMUNOGLOBULIN-G CONCENTRATIONS IN DOGS WITH INFLAMMATORY BOWEL-DISEASE

Objective-To evaluate lavage analytes as markers of mucosal inflammati on in healthy dogs and dogs with inflammatory bowel disease (IBD). Des ign-Case control study. Animals-9 healthy dogs and 10 dogs with IBD. P rocedure-A polyethylene glycol electrolyte solution was administered i nto the dogs' colons via a rectal balloon catheter prior to colonoscop y. Lavage solution was allowed to remain intraluminally for 30 minutes and then was withdrawn. Lavage supernatant samples were immediately a nalyzed for total protein, IgG, and nitrite concentrations and myelope roxidase activity. Mucosal biopsy specimens were obtained from the des cending colon and histologically reviewed. Results-All dogs with IBD h ad mild to severe lymphocytic-plasmacytic colitis, whereas 8 of 9 heal thy dogs did not have substantial mucosal inflammation. Myeloperoxidas e activity was not detected in lavage samples from healthy dogs or dog s with IBD. Total protein concentration was not significantly differen t between groups. Mean nitrite and IgG concentrations were significant ly higher in samples from dogs with IBD (1.83 nmol/ml and 46 mg/dl, re spectively), compared with samples from healthy dogs (0.245 nmol/ml an d undetectable concentrations, respectively). Severity of lesions was not correlated with nitrite or IgG concentration. Clinical Implication s-Assay of nitrite and IgG concentrations in colonic lavage fluid is a simple, objective means of evaluating mucosal inflammation in dogs wi th IBD. Potential uses include monitoring response to treatment and ev aluation of complex cases of chronic intestinal inflammation.