Expression of cyclooxygenase isoforms in ulcerated tissues of the nonglandular portion of the stomach in horses.
OBJECTIVE
To characterize the expression of the cyclooxygenase (COX)-1 and COX-2 isoforms in naturally occurring ulcers of the nonglandular portion of the stomach in horses. SPECIMEN POPULATION: 38 specimens from ulcerated stomachs and 10 specimens from healthy stomachs.


METHODS
Specimens were collected at an abbatoir; for each specimen of squamous gastric mucosa, 1 portion was fixed in neutral-buffered 10% formalin for immunohistochemical analysis and another was frozen at -70 degrees C for immunoblotting analysis. Immunoreactivity to 2 antibodies, MF241 (selective for COX-1) and MF243 (selective for COX-2), was evaluated by a veterinary pathologist using a scoring system. Expression of COX-1 and COX-2 was confirmed by use of immunoblotting analyses.


RESULTS
All specimens from healthy stomachs strongly expressed COX-1, whereas only 2 of 10 expressed COX-2. The expression of both isoforms varied greatly in the ulcerated mucosal specimens. Expression of COX-1 was significantly lower and expression of COX-2 was significantly higher in ulcerated versus healthy specimens.


CONCLUSIONS
Increased expression of COX-2 in gastric ulcers of the squamous portion of the stomach in horses suggested a role for this enzyme in gastric ulcer healing.
Rodrigues
Natália L F
NL
Département de Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, QC J2S 7C6, Canada.
Doré
Monique
M
Doucet
Michèle Y
MY
D000818:Animals; D051545:Cyclooxygenase 1 / Q000235:genetics* / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism; D005753:Gastric Mucosa / Q000201:enzymology* / Q000473:pathology; D006734:Horse Diseases / Q000201:enzymology* / Q000473:pathology; D006736:Horses; D015151:Immunoblotting; D007150:Immunohistochemistry; D012016:Reference Values; D013270:Stomach / Q000201:enzymology*; D013276:Stomach Ulcer / Q000201:enzymology / Q000473:pathology / Q000662:veterinary*
D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2