Topical effect of various agents on gelatinase activity in the tear film of normal dogs.
OBJECTIVE
To evaluate the topical effect of various agents, currently used in the treatment of melting ulcers, on gelatinase activity present in the tear film of normal dogs.


METHODS
Eight normal adult beagles.


METHODS
Each animal received the following agents: cyclosporine A 1%, N-acetylcysteine 10%, ciprofloxacin 0.3%, ethylenediaminetetraacetic acid (EDTA) 1%, doxycycline 0.001%, polysulfated glycosaminoglycans (PSGAG) 5%, autoserum, and artificial tears during a 48-h period following a Latin square design. Tear samples were collected with micro-capillary pipettes following a corneal surface irrigation of each eye with sterile saline on four different occasions. Basal and total gelatinase activities were evaluated by optical density after processing in a commercial gelatinase activity assay. From the optical density ratio, a semi-quantitative measure of gelatinase activity was obtained. Basal and total activities were measured in all samples.


RESULTS
The lowest total gelatinase activity, representing a percent decline in the enzyme activity although not significant, was observed 1 h after the last treatment in seven out of the eight ophthalmic agents; EDTA (68%), ciprofloxacin (76%), cyclosporine A (68%), doxycycline (47%), artificial tears (26%), PSGAG (25%), and N-acetylcysteine (20%). However, only the reduction observed with EDTA 6 h after the last treatment was significantly lower compared to the reduction observed with the artificial tears.


CONCLUSIONS
This study indicated that only EDTA was able to significantly reduce the gelatinase activity in a persistent manner in the tear film of normal canine eyes. Further studies will be required to evaluate the effect of EDTA under ulcerative conditions and to more accurately ascertain the potential in vivo effect of the other agents.
Couture
Simon
S
Département des Sciences Cliniques, Faculté de Médicine Vétérinaire, Université de Montréal, Québec, Canada, J2S 7C6.
Doucet
Michèle
M
Moreau
Maxime
M
Carrier
Michel
M
D000111:Acetylcysteine / Q000008:administration & dosage; D000287:Administration, Topical; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D002939:Ciprofloxacin / Q000008:administration & dosage; D016572:Cyclosporine / Q000008:administration & dosage; D004285:Dogs; D004318:Doxycycline / Q000008:administration & dosage; D004492:Edetic Acid / Q000008:administration & dosage; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D018093:Gelatinases / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000008:administration & dosage; D009883:Ophthalmic Solutions / Q000008:administration & dosage; D013666:Tears / Q000201:enzymology*; D013997:Time Factors
D000900:Anti-Bacterial Agents; D004791:Enzyme Inhibitors; D006025:Glycosaminoglycans; D009883:Ophthalmic Solutions; D002939:Ciprofloxacin; D016572:Cyclosporine; D004492:Edetic Acid; D018093:Gelatinases; D004318:Doxycycline; D000111:Acetylcysteine