Anti-Inflammatory Effect of Melatonin for Cataract Surgery in Dogs

SANDE, PABLO; ROSENSTEIN, RUTH; SAENZ, DANIEL

Fort Lauderdale, U.S.A.

Congreso; 2011 The Association for Research in Vision and Ophthalmology Annual Meeting; 2010

The Association for Research in Vision and Ophthalmology

Abstract Purpose:Cataract is a major cause of blindness in dogs. The more frequent etiologies for cataract in dogs are from a diabetic and hereditary origin. While the treatment is cataract removal, the therapeutic success depends largely on post-surgical inflammation. The commonly used compounds (corticosteroids or non-steroidal anti-inflammatory drugs,) are effective but exhibit significant side effects. We have demonstrated that melatonin is a potent ocular anti-inflammatory without adverse effects in the hamster. The aim of this study was to analyze the anti-inflammatory effect of melatonin for cataract surgery in dogs. Methods:With the consent of the owners, dogs were divided into 4 groups, submitted to different treatments, starting 3 days before surgery, as follows: group A: dogs with hereditary cataract treated with dexamethasone (1 drop/6 h), group B: dogs with hereditary cataract treated with melatonin (3 mg/12 h), group C: diabetic dogs with carprofen (1 mg/kg /12 h) + diclofenac (1 drop/6 h), and group D: diabetic dogs with melatonin (3 mg/12 h). All groups were treated with tobramicin (1 drop/8 h) and atropine (1 drop/12 h). The surgery was performed by phacoemulsification. During a period of 120 days after surgery, dogs were evaluated periodically using a slit lamp, direct and indirect ophthalmoscopy, and tonometry. At 2, 7, and 20 days post-surgery, clinical severity of the inflammatory signs was assessed by a clinical score, considering blepharospasm, Tyndall effect, miosis, episcleral veins, alterations in the cornea and intraocular pressure (IOP)) and at 120 days post-surgery, the presence of sequelae (corneal edema, synechiae, and posterior capsule opacification) was analyzed. Statistical analysis was performed using Mann-Whitney and Tukey’s tests. Results:In non-diabetic animals, results obtained with melatonin did not differ from those obtained with dexamethasone at 2 and 7 days post-surgery, while at 20 days post-surgery, the inflammation was lower in the group treated with melatonin (p <0.05). In the group of diabetic animals, post-surgical inflammation was lower in the group treated with melatonin than in the carprofen-treated eyes at all the examined time-points (p <0.01). The percentage of eyes showing sequelae was: 33%, 11%, 44%, 11%, for groups A, B, C and D, respectively. The IOP did not differ among groups. Conclusions:These results support the use of melatonin as an anti-inflammatory treatment for cataract surgery in dogs.