Evaluation of the relationship between lesions in the gastroduodenal region and cyclooxygenase expression in clinically normal dogs.
OBJECTIVE
To determine whether clinically normal dogs have lesions in the pylorus and duodenum and to examine the expression of cyclooxygenase (COX) isoforms in the pylorus and duodenum of these dogs.


METHODS
27 clinically normal dogs.


METHODS
Physical examination was performed on clinically normal dogs from animal shelters and research projects; the dogs were then euthanized. After the dogs were euthanized, the pylorus and duodenum were photographed and scored for gross appearance of lesions. Samples were obtained for histologic evaluation and determination of COX expression via western blot analyses. Tissues from the pylorus and duodenum were categorized as normal, inflamed, or eroded on the basis of histologic analysis. Each histologic category of tissue was then evaluated to determine the correlation with gross appearance and COX expression.


RESULTS
Of the 27 dogs, 5 had unremarkable histologic findings in the pylorus and duodenum. Inflammation was found in the pylorus of 10 dogs and in the duodenum of 5 dogs. Epithelial erosion was detected in the pylorus of 1 dog and in the duodenum of 3 dogs. Gross appearance was not significantly correlated with histologic appearance. Expression of COX-1 was not upregulated by inflammation, whereas COX-2 expression was increased by inflammation or erosion.


CONCLUSIONS
Dogs that appear to be clinically normal may have underlying gastroduodenal lesions associated with upregulation of COX-2. Because of the inability to determine this during routine physical examination, practitioners should be aware of this potential situation when prescribing COX inhibitors.
Wooten
Jenna G
JG
Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
Lascelles
B Duncan X
BD
Cook
Vanessa L
VL
Law
J Mac
JM
Blikslager
Anthony T
AT
D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D051545:Cyclooxygenase 1 / Q000096:biosynthesis*; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D004283:Dog Diseases / Q000201:enzymology* / Q000473:pathology; D004285:Dogs / Q000378:metabolism*; D004382:Duodenitis / Q000201:enzymology / Q000473:pathology / Q000662:veterinary; D004386:Duodenum / Q000201:enzymology* / Q000473:pathology; D005260:Female; D005756:Gastritis / Q000201:enzymology / Q000473:pathology / Q000662:veterinary; D007150:Immunohistochemistry / Q000662:veterinary; D007413:Intestinal Mucosa / Q000201:enzymology* / Q000473:pathology; D008297:Male; D011708:Pylorus / Q000201:enzymology* / Q000473:pathology; D018709:Statistics, Nonparametric
D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2